F1-CONSULT https://www.f1-consult.com Our Network For Your Network Wed, 15 Nov 2023 08:54:05 +0000 en-US hourly 1 https://wordpress.org/?v=7.1.3 https://www.f1-consult.com/wp-content/uploads/2018/01/cropped-F1-CONSULT-favicon-32x32.png F1-CONSULT https://www.f1-consult.com 32 32 CISCO – AnyConnect – The VPN connection to the secure gateway was interrupted and could not be automatically re-established https://www.f1-consult.com/cisco/cisco-security/anyconnect/anyconnect/ Wed, 15 Nov 2023 08:54:05 +0000 https://www.f1-consult.com/?p=4906

The VPN connection to the secure gateway was interrupted and could not be automatically re-established. A new connection is necessary, which requires re-authentication.

Client Issue:

  • Flakey connections
  • nondeterministic reconnects

Trouble shooting:

  • Does the client have IPv4 or IPv6 or dual stack in local LAN?
  • Does the local provider provide IPv4 or IPv6 or dual stack in local LAN?
  • IPv4 and IPv6 Traceroute from the vpn client towards the VPN gateways
  • If there are multiple gateways, traceroute to all of them
  • Check MTU Size:

Analysis:

  • Is the client next hop on the provider side showing 192.0.0.1 in the traceroue?
  • If so, that’s an indication of them having deployed DS-LITE
  • DS-Lite is a IPv6 transition mechanism widely deployed in Europe by cable providers such as Liberty Global (like UPC, Unitymedia, …), like Vodafone, Versatel, Kabel Deutschland and others.
  • That goes together with AFTR (carrier grade NAT system) to transition users from their native IPv6 home connections to the IPv4 world.
  • Therefore multiple users share a single external IPv4 address using this system.
  • Please check rfc6333 for more information
  • That doesn’t go well with VPN Tunnel technologies like Cisco AnyConnect Secure Mobility Client

Solution:

  • Open a ticket with the DSL provider and ask them to change your connection from DS-LITE towards DS.
  • Most cases they need a valid reason to do so. Tell them that you need native dual stack for business so that your VPN client can work properly.
  • Good Luck!
]]>
CISCO – AnyConnect – Windows Autostart https://www.f1-consult.com/cisco/cisco-security/anyconnect/anyconnect-2/ Wed, 15 Nov 2023 08:43:41 +0000 https://www.f1-consult.com/?p=4910

CISCO Anyconnect Autostart

Windows:

\Computer\HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Run\Cisco AnyConnect Secure Mobility Agent for Windows"

Autostart enabled:

"C:\Program Files (x86)\Cisco\Cisco AnyConnect Secure Mobility Client\vpnui.exe" -autolaunched

Autostart disabled:

"C:\Program Files (x86)\Cisco\Cisco AnyConnect Secure Mobility Client\vpnui.exe"
]]>
Apple products on enterprise networks https://www.f1-consult.com/apple/apple-products-on-enterprise-networks/ Thu, 28 Sep 2023 17:21:37 +0000 https://www.f1-consult.com/?p=4900 Device setup

Apple devices need access to the following hosts during setup, or when installing, updating, or restoring the operating system.

HostsPortsProtocolOSDescriptionSupports proxies
albert.apple.com443TCPiOS, iPadOS, tvOS, and macOSDevice activationYes
captive.apple.com443, 80TCPiOS, iPadOS, tvOS, and macOSInternet connectivity validation for networks that use captive portalsYes
gs.apple.com443TCPiOS, iPadOS, tvOS, and macOS Yes
humb.apple.com443TCPiOS, iPadOS, tvOS, and macOS Yes
static.ips.apple.com443, 80TCPiOS, iPadOS, tvOS, and macOS Yes
sq-device.apple.com443TCPiOS and iPadOSeSIM activation—
tbsc.apple.com443TCPiOS, iPadOS, tvOS, and macOS Yes
time-ios.apple.com123UDPiOS, iPadOS, and tvOSUsed by devices to set their date and time—
time.apple.com123UDPiOS, iPadOS, tvOS, and macOSUsed by devices to set their date and time—
time-macos.apple.com123UDPmacOS onlyUsed by devices to set their date and time—

Device management

Apple devices enrolled in MDM need access to the following hosts and domains.

HostsPortsProtocolOSDescriptionSupports proxies
*.push.apple.com443, 80, 5223, 2197TCPiOS, iPadOS, tvOS, and macOSPush notificationsLearn more about APNs and proxies.
deviceenrollment.apple.com443TCPiOS, iPadOS, tvOS, and macOSDEP provisional enrollment—
deviceservices-external.apple.com443TCPiOS, iPadOS, tvOS, and macOS —
gdmf.apple.com
443TCPiOS, iPadOS, tvOS, and macOSUsed by an MDM server to identify which software updates are available to devices that use managed software updatesYes
identity.apple.com443TCPiOS, iPadOS, tvOS, and macOSAPNs certificate request portalYes
iprofiles.apple.com443TCPiOS, iPadOS, tvOS, and macOSHosts enrollment profiles used when devices enroll in Apple School Manager or Apple Business Manager through Device EnrollmentYes
mdmenrollment.apple.com443TCPiOS, iPadOS, tvOS, and macOSMDM servers to upload enrollment profiles used by clients enrolling through Device Enrollment in Apple School Manager or Apple Business Manager, and to look up devices and accountsYes
setup.icloud.com443TCPiOS and iPadOSRequired to log in with a Managed Apple ID on Shared iPad—
vpp.itunes.apple.com443TCPiOS, iPadOS, tvOS, and macOSMDM servers to perform operations related to Apps and Books, like assigning or revoking licenses on a deviceYes

Apple Business Manager and Apple School Manager

Administrators and managers need access to the following hosts and domains in order to administer and manage Apple Business Manager and Apple School Manager.

HostsPortsProtocolOSDescriptionSupports proxies
*.business.apple.com
443, 80TCP–Apple Business Manager—
*.school.apple.com443, 80TCP–Apple School Manager—
appleid.cdn-apple.com443TCP–Login authenticationYes
idmsa.apple.com443TCP–Login authenticationYes
*.itunes.apple.com443, 80TCP–Apps and BooksYes
*.mzstatic.com443TCP–Apps and Books—
api.ent.apple.com443TCP–Apps and Books (ABM)—
api.edu.apple.com443TCP–Apps and Books (ASM)—
statici.icloud.com443TCP–Device icons—
*.vertexsmb.com443TCP–Validating tax-exempt status
—
www.apple.com443TCP–Fonts for certain languages
—
upload.appleschoolcontent.com22SSH–SFTP uploadsYes

Employees and students using Managed Apple IDs need access to the following host in order to look up others in their business or school when composing messages or sharing documents.

HostsPortsProtocolOSDescriptionSupports proxies
ws-ee-maidsvc.icloud.com443, 80TCPiOS, iPadOS, and macOS
User lookup service—

Apple Business Essentials device management

Administrators and devices managed by Apple Business Essentials need access to the following hosts and domains, along with those listed above for Apple Business Manager.

HostsPortsProtocolOSDescriptionSupports proxies
axm-adm-enroll.apple.com443TCPiOS, iPadOS, tvOS, and macOSDEP enrollment server—
axm-adm-mdm.apple.com443TCPiOS, iPadOS, tvOS, and macOSMDM server—
axm-adm-scep.apple.com443TCPiOS, iPadOS, tvOS, and macOSSCEP server—
axm-app.apple.com443TCPiOS, iPadOS, and macOSView and manage apps and devices—
*.apple-mapkit.com443TCPiOS and iPadOSView the location of devices in Managed Lost Mode—
icons.axm-usercontent-apple.com443TCPmacOSCustom Package icons—

Classroom and Schoolwork

Student and Teacher devices using the Classroom or Schoolwork apps need access to the following hosts, as well as those listed in the Apple ID and iCloud sections below.

HostsPortsProtocolOSDescriptionSupports proxies
s.mzstatic.com443TCPiPadOS and macOSClassroom and Schoolwork device verification—
play.itunes.apple.com443TCPiPadOS and macOSClassroom and Schoolwork device verification—
ws-ee-maidsvc.icloud.com443TCPiPadOS and macOSClassroom and Schoolwork class roster service—
ws.school.apple.com443TCPiPadOS and macOSClassroom and Schoolwork class roster service—
pg-bootstrap.itunes.apple.com443TCPiPadOSSchoolwork handout service—
cls-iosclient.itunes.apple.com443TCPiPadOSSchoolwork handout service—
cls-ingest.itunes.apple.com443TCPiPadOSSchoolwork handout service—

Software updates

Make sure you can access the following ports for updating macOS, apps from the Mac App Store, and for using content caching.

macOS, iOS, iPadOS, watchOS, and tvOS

Apple devices need access to the following hosts when installing, restoring, and updating iOS, iPadOS, macOS, watchOS, and tvOS.

HostsPortsProtocolOSDescriptionSupports proxies
appldnld.apple.com80TCPiOS, iPadOS, and watchOSiOS, iPadOS, and watchOS updates—
configuration.apple.com443TCPmacOS onlyRosetta 2 updates—
gdmf.apple.com443TCPiOS, iPadOS, tvOS, watchOS, and macOSSoftware update catalog—
gg.apple.com443, 80TCPiOS, iPadOS, tvOS, watchOS, and macOSiOS, iPadOS, tvOS, watchOS, and macOS updatesYes
gs.apple.com443, 80TCPiOS, iPadOS, tvOS, watchOS, and macOSiOS, iPadOS, tvOS, watchOS, and macOS updatesYes
ig.apple.com443TCPmacOS onlymacOS updatesYes
mesu.apple.com443, 80TCPiOS, iPadOS, tvOS, watchOS, and macOSHosts software update catalogs—
ns.itunes.apple.com443TCPiOS, iPadOS, and watchOS Yes
oscdn.apple.com443, 80TCPmacOS onlymacOS Recovery—
osrecovery.apple.com443, 80TCPmacOS onlymacOS Recovery—
skl.apple.com443TCPmacOS onlymacOS updates—
swcdn.apple.com443, 80TCPmacOS onlymacOS updates—
swdist.apple.com443TCPmacOS onlymacOS updates—
swdownload.apple.com443, 80TCPmacOS onlymacOS updatesYes
swscan.apple.com443TCPmacOS onlymacOS updates—
updates-http.cdn-apple.com80TCPiOS, iPadOS, tvOS, and macOSSoftware update downloads—
updates.cdn-apple.com443TCPiOS, iPadOS, tvOS, and macOSSoftware update downloads—
xp.apple.com443TCPiOS, iPadOS, tvOS, and macOS Yes

App Store

Apple devices need access to the following hosts and domains for installing and updating apps.

HostsPortsProtocolOSDescriptionSupports proxies
*.itunes.apple.com443, 80TCPiOS, iPadOS, tvOS, and macOSStore content such as apps, books, and musicYes
*.apps.apple.com443TCPiOS, iPadOS, tvOS, and macOSStore content such as apps, books, and musicYes
*.mzstatic.com443TCPiOS, iPadOS, tvOS, and macOSStore content such as apps, books, and music—
itunes.apple.com443, 80TCPiOS, iPadOS, tvOS, and macOS Yes
ppq.apple.com443TCPiOS, iPadOS, tvOS, and macOSEnterprise App validation—

Carrier updates

Cellular devices need access to the following hosts to install carrier bundle updates.

HostsPortsProtocolOSDescriptionSupports proxies
appldnld.apple.com80TCPiOS and iPadOSCellular carrier bundle updates—
appldnld.apple.com.edgesuite.net80TCPiOS and iPadOSCellular carrier bundle updates—
itunes.com80TCPiOS and iPadOSCarrier bundle update discovery—
itunes.apple.com443TCPiOS and iPadOSCarrier bundle update discovery—
updates-http.cdn-apple.com80TCPiOS and iPadOSCellular carrier bundle updates—
updates.cdn-apple.com443TCPiOS and iPadOSCellular carrier bundle updates—

Content caching

A Mac that provides content caching needs access to the following hosts, as well as the hosts listed in this document that provide Apple content such as software updates, apps, and additional content.

HostsPortsProtocolOSDescriptionSupports proxies
lcdn-registration.apple.com443TCPmacOS onlyServer registrationYes
suconfig.apple.com80TCPmacOS only

Configuration—
xp-cdn.apple.com443TCPmacOS onlyReportingYes

Clients of macOS content caching need access to the following hosts.

HostsPortsProtocolOSDescriptionSupports proxies
lcdn-locator.apple.com443TCPiOS, iPadOS, tvOS, and macOSContent caching locator service—
serverstatus.apple.com
443TCPmacOS onlyContent caching client public IP determination—

App features

Apple devices may need access to the following hosts to use certain app features. 

App notarization is required for apps to run on macOS 10.14 and later. Gatekeeper requires access to Apple servers to verify notarization, unless the app developer has stapled the notarization ticket to the app. App developers can learn more about customizing the notarization workflow.

App validation is used to certify that a valid instance of the app is running. App developers can learn more about establishing an app’s integrity.

HostsPortsProtocolOSDescriptionSupports proxies
api.apple-cloudkit.com443TCPmacOSApp notarization—
*.appattest.apple.com443TCPiOS, iPadOS, and macOSApp validation, Touch ID and Face ID authentication for websites—

Beta updates

Apple devices need access to the following hosts to sign in to Beta Updates and report feedback using the Feedback Assistant app.

HostsPortProtocolOSDescriptionSupports proxies
bpapi.apple.com443TCPiOS, iPadOS, tvOS, watchOS, and macOSBeta update enrollmentYes
cssubmissions.apple.com
443TCPiOS, iPadOS, tvOS, and macOSUsed by Feedback Assistant to upload files

Yes
fba.apple.com

443TCPiOS, iPadOS, tvOS, and macOS

Used by Feedback Assistant to file and view feedback

Yes

Apple diagnostics

Apple devices might access the following host in order to perform diagnostics used to detect a possible hardware issue.

HostsPortsProtocolOSDescriptionSupports proxies
diagassets.apple.com443TCPiOS, iPadOS, tvOS, and macOSUsed by Apple devices to help detect possible hardware issuesYes

Domain Name System resolution

Encrypted Domain Name System (DNS) resolution in iOS 14, iPadOS 14, tvOS 14, and macOS Big Sur and later uses the following host.

HostsPortsProtocolOSDescriptionSupports proxies
doh.dns.apple.com443TCPiOS, iPadOS, tvOS, and macOSUsed for DNS over HTTPS (DoH)Yes

Certificate validation

Apple devices must be able to connect to the following hosts to validate digital certificates used by the hosts in this article.

HostsPortsProtocolOSDescriptionSupports proxies
certs.apple.com80, 443TCPiOS, iPadOS, tvOS, and macOSCertificate validation—
crl.apple.com80TCPiOS, iPadOS, tvOS, and macOSCertificate validation—
crl.entrust.net80TCPiOS, iPadOS, tvOS, and macOSCertificate validation—
crl3.digicert.com80TCPiOS, iPadOS, tvOS, and macOSCertificate validation—
crl4.digicert.com80TCPiOS, iPadOS, tvOS, and macOSCertificate validation—
ocsp.apple.com80TCPiOS, iPadOS, tvOS, and macOSCertificate validation—
ocsp.digicert.cn80TCPiOS, iPadOS, tvOS, and macOSCertificate validation in China—
ocsp.digicert.com80TCPiOS, iPadOS, tvOS, and macOSCertificate validation—
ocsp.entrust.net80TCPiOS, iPadOS, tvOS, and macOSCertificate validation—
ocsp2.apple.com443TCPiOS, iPadOS, tvOS, and macOSCertificate validation—
valid.apple.com443TCPiOS, iPadOS, tvOS, and macOSCertificate validationYes

Apple ID

Apple devices must be able to connect to the following hosts in order to authenticate an Apple ID. This is required for all services that use an Apple ID, such as iCloud, app installation, and Xcode.

HostsPortsProtocolOSDescriptionSupports proxies
appleid.apple.com
443TCPiOS, iPadOS, tvOS, and macOS
Apple ID authentication in Settings and System Preferences
Yes
appleid.cdn-apple.com
443TCPiOS, iPadOS, tvOS, and macOS
Apple ID authentication in Settings and System Preferences
Yes
idmsa.apple.com443TCPiOS, iPadOS, tvOS, and macOSApple ID authenticationYes
gsa.apple.com443TCPiOS, iPadOS, tvOS, and macOSApple ID authenticationYes

iCloud

In addition to the Apple ID hosts listed above, Apple devices must be able to connect to hosts in the following domains to use iCloud services.

HostsPortsProtocolOSDescriptionSupports proxies
*.apple-cloudkit.com443TCPiOS, iPadOS, tvOS, and macOSiCloud services—
*.apple-livephotoskit.com443TCPiOS, iPadOS, tvOS, and macOSiCloud services—
*.apzones.com443TCPiOS, iPadOS, tvOS, and macOSiCloud services in China—
*.cdn-apple.com443TCPiOS, iPadOS, tvOS, and macOSiCloud services—
*.gc.apple.com
443TCPiOS, iPadOS, tvOS, and macOS
iCloud services
—
*.icloud.com443TCPiOS, iPadOS, tvOS, and macOSiCloud services—
*.icloud.com.cn
443TCPiOS, iPadOS, tvOS, and macOS
iCloud services in China
—
*.icloud.apple.com443TCPiOS, iPadOS, tvOS, and macOSiCloud services—
*.icloud-content.com443TCPiOS, iPadOS, tvOS, and macOSiCloud services—
*.iwork.apple.com443TCPiOS, iPadOS, tvOS, and macOSiWork documents—
mask.icloud.com443UDPiOS, iPadOS, macOSiCloud Private Relay—
mask-h2.icloud.com443TCPiOS, iPadOS, macOSiCloud Private Relay—
mask-api.icloud.com443TCPiOS, iPadOS, macOSiCloud Private RelayYes

Siri and Search

Apple devices must be able to connect to the following hosts to process Siri requests, including dictation and searching in Apple apps.

HostsPortsProtocolOSDescriptionSupports proxies
guzzoni.apple.com443TCPiOS, iPadOS, and macOSSiri and dictation requests—
*.smoot.apple.com443TCPiOS, iPadOS, and macOSSearch services, including Siri, Spotlight, Lookup, Safari, News, Messages and Music—

Associated Domains

Apple devices must be able to connect to the following hosts to use Associated Domains in iOS 14, iPadOS 14, and macOS Big Sur and later. Associated Domains underpin universal links, a feature that allows an app to present content in place of all or part of its website. Handoff, App Clips, and single sign-on extensions all use Associated Domains.

HostsPortsProtocolOSDescriptionSupports proxies
app-site-association.cdn-apple.com443TCP, UDPiOS, iPadOS, and macOSAssociated domains for universal links—
app-site-association.networking.apple443TCP, UDPiOS, iPadOS, and macOSAssociated domains for universal links—

Tap to Pay on iPhone

To use a payment app to accept contactless payments, an iPhone must be able to reach the following hosts.

HostsPortsProtocolOSDescriptionSupports proxies
pos-device.apple.com443TCP, UDPiOSTap to Pay on iPhoneYes
humb.apple.com443TCPiOSTap to Pay on iPhone setupYes
phonesubmissions.apple.com443TCPiOSOptional analytics sharingYes

Additional content

Apple devices must be able to connect to the following hosts to download additional content. Some additional content might also be hosted on third-party content distribution networks.

HostsPortsProtocolOSDescriptionSupports proxies
audiocontentdownload.apple.com80, 443TCPiOS, iPadOS, and macOSGarageBand downloadable content—
devimages-cdn.apple.com
80, 443TCPmacOS onlyXcode downloadable components—
download.developer.apple.com80, 443TCPmacOS onlyXcode downloadable components—
playgrounds-assets-cdn.apple.com443TCPiPadOS and macOSSwift Playgrounds—
playgrounds-cdn.apple.com443TCPiPadOS and macOSSwift Playgrounds—
sylvan.apple.com
80, 443TCPtvOS only
Apple TV screen savers
—

More at Apple HT210060

]]>
IPv6 – networking acronyms and abbreviations https://www.f1-consult.com/ipv6/ipv6/ Fri, 09 Jun 2023 17:43:37 +0000 https://www.f1-consult.com/?p=4893
IPv6: Internet Protocol version 6
CIDR: Classless Inter-Domain Routing
ICMPv6: Internet Control Message Protocol version 6
NDP: Neighbor Discovery Protocol
SLAAC: Stateless Address Autoconfiguration
DHCPv6: Dynamic Host Configuration Protocol version 6
RA: Router Advertisement
RDNSS: Recursive Domain Name Server Option
DHCPv6-PD: Dynamic Host Configuration Protocol version 6 Prefix Delegation
MLD: Multicast Listener Discovery
LL: Link-Local
UL: Unique Local
ULA: Unique Local Address
EUI-64: Extended Unique Identifier-64
ULA-C: Unique Local Address-Constrained
LLA: Link-Local Address
LAN: Local Area Network
WAN: Wide Area Network
MTU: Maximum Transmission Unit
NAT64: Network Address Translation IPv6 to IPv4
DS-Lite: Dual-Stack Lite
6to4: IPv6 over IPv4
Teredo: IPv6 over IPv4 Tunneling
6RD: IPv6 Rapid Deployment
DNS: Domain Name System
DNSSEC: Domain Name System Security Extensions
DNS64: DNS IPv6 to IPv4 Translation
DSCP: Differentiated Services Code Point
QoS: Quality of Service
FQDN: Fully Qualified Domain Name
ACL: Access Control List
VPN: Virtual Private Network
IPSec: Internet Protocol Security
NAT: Network Address Translation
BGP: Border Gateway Protocol
OSPFv3: Open Shortest Path First version 3
MPLS: Multi-Protocol Label Switching
IoT: Internet of Things
IoT6: IPv6-based Internet of Things
]]>
Cisco Transceiver Modules – Data Sheets https://www.f1-consult.com/cisco/cisco-transceiver-modules-data-sheets/ Wed, 01 Feb 2023 11:37:09 +0000 https://www.f1-consult.com/?p=4878 Transceiver-modules

Data Sheets

Optical transceiver modules

800G modules

800G modules

Double your port capacity with QSFP-DD800 while preserving backward compatibility to lower speed QSFP modules.

400G modules

400G modules

Migrate to 400G connectivity with QSFP-DD modules that provide super-high density and backwards compatibility.

100G modules

100G modules

Deploy high-density and low-power connectivity in your data center, high-performance computing, and service provider networks.

50G modules

50G modules

Implement high-capacity single-lane connectivity for service provider and enterprise access networks, and data center applications.

40G modules

40G modules

Meet high-performance connectivity requirements of campus, data center, and cloud deployments.

25G modules

25G modules

Deploy high-density and low-power SFP28 connectivity for data center and high-performance computing networks applications.

10G modules

10G modules

Support a broad range of port types with modules optimized for the requirements of your 10G applications.

]]>
CISCO – AnyConnect – AnyConnect Profiles location https://www.f1-consult.com/cisco/cisco-security/anyconnect/anyconnect-2-2/ Tue, 22 Mar 2022 21:42:12 +0000 https://www.f1-consult.com/?p=4836

Where are the AnyConnect Profiles located?

XML and profile files are stored locally to the users machine.The location varies based on OS.

Windows XP:

%ALLUSERSPROFILE%\Application Data\Cisco\Cisco AnyConnect Secure Mobility Client\Profile

Windows Vista:

%ProgramData%\Cisco\Cisco AnyConnect Secure Mobility Client\Profile

Windows 7:

%ProgramData%\Cisco\Cisco AnyConnect Secure Mobility Client\Profile

Windows 8:

%ProgramData%\Cisco\Cisco AnyConnect Secure Mobility Client\Profile

Windows 10:

%ProgramData%\Cisco\Cisco AnyConnect Secure Mobility Client\Profile

Mac OS X:

/opt/cisco/anyconnect/profile

Linux.:

/opt/cisco/anyconnect/profile
]]>
LINUX – nmcli command examples (cheatsheet), compare nm-settings with if-cfg file https://www.f1-consult.com/linux/lan/nmcli/ Mon, 07 Jun 2021 21:47:01 +0000 https://www.f1-consult.com/?p=4752

Table of Contents

nmcli examples. nmcli cheatsheet in CentOS/RHEL 7/8. nmcli command exmaples. nmcli con reload. nmcli help. add ethernet connection using nmcli. nmclic command examples cheatsheet in linux. add bond connection using nmcli in linux. add and configure network teaming using nmcli. nmcli command cheatsheet. configure networkmanager using nmcli. nmcli examples. nmclic command examples cheatsheet. exit an existing connection with nmcli. nmcli command examples. nmcli enable dhcp. man nmcli examples. nmcli rename connection. nmcli remove static ipv4 address. nmcle cheat sheet. nmcli remove dns

Understanding nmcli

  • nmcli is a command-line tool for controlling NetworkManager and reporting network status.
  • It can be utilised as a replacement for nm-applet or other graphical clients. nmcli is used to create, display, edit, delete, activate, and deactivate network connections, as well as control and display network device status.
  • Connections are stored in configuration files
  • The NetworkManager service must be running to manage these files

Compare nm-settings with ifcfg-* directives (IPv4)

nmcli con mod ifcfg-* file Effect
ipv4.method manual BOOTPROTO=none IPv4 address configured statically
ipv4.method auto BOOTPROTO=dhcp Will look for configuration settings from a DHCPv4 server
ipv4.address "192.168.0.10/24" IPADDR=192.168.0.10
PREFIX=24
Set static IPv4 address, network prefix
ipv4.gateway 192.168.0.1 GATEWAY=192.168.0.1 Set IPv4 Gateway
ipv4.dns 8.8.8.8 DNS1=8.8.8.8 Modify /etc/resolv.conf to use this nameserver
ipv4.dns-search example.com DOMAIN=example.com Modify /etc/resolv.conf to use this domain in the search directive
ipv4.ignore-auto-dns true PEERDNS=no Ignore DNS Server information from the DHCP Server
connection.autoconnect yes ONBOOT=yes Automatically activate this connection on boot
connection.id eth0 NAME=eth0 The name of this connection
connection.interface-name eth0 DEVICE=eth0 The connection is bound to the network interface with this name
802-3-ethernet.mac-address 08:00:27:4b:7a:80 HWADDR=08:00:27:4b:7a:80 The connection is bound to the network interface with this MAC Address
ipv4.never-default no DEFROUTE=yes Never use provided interface’s gateway as default gateway

Compare nm-settings with ifcfg-* directives (IPv6)

nmcli con mod ifcfg-* file Effect
ipv6.method manual IPV6_AUTOCONF=no IPv6 is configured statically
ipv6.method auto IPV6_AUTOCONF=yes Will configure network settings using SLAAC from router advertisements.
ipv6.method dhcp IPV6_AUTOCONF=no
DHCPV6C=yes
Will configure network settings by using DHCPv6, but not SLAAC
ipv6 . addresses
"2001:db8::a/64 2001:db8::1"
IPV6ADDR=2001:db8::a/64
IPV6_DEFAULTGW=2001:db8::1
Sets static IPv6 Address and Gateway
ipv6.dns . . . DNS0=. . . Modify /etc/resolv.conf to use this nameserver
ipv6.dns-search example.com DOMAIN=example.com Modify /etc/resolv.conf to use to use this domain in the search directive
ipv6.ignore-auto-dns true IPV6_PEERDNS=no Ignore DNS server information from the DHCP server
connection.autoconnect yes ONBOOT=YES Automatically activates the connection at boot
connection.id eth0 NAME=eth0 The name of this connection
connection.interface-name eth0 DEVICE=eth0 The connection is bound to this network interface with this name
802-3-ethernet.mac-address . . . HWADDR=. . . The connection is bound to the network interface with this MAC Address

Brief list of nmcli commands syntax

Command Purpose
nmcli dev status Show the Network Manager status of all network interfaces
nmcli con show List all connections
nmcli con show name List the current settings for the connection name
nmcli con add con-name name .. Add a new connection named name
nmcli con mod name .. Modify the connection name
nmcli con reload Tell networkManager to reread the configuration files (useful after they have been edited by hand)
nmcli con up name Activate the connection name
nmcli dev dis dev Deactivate and disconnect the current connection on the network interface dev
nmcli con del name Delete the connection name and its configuration file

nmcli command examples (cheatsheet)

Below are some of the chosen nmcli command examples

1. Check if NetworkManager is running

You can use below command to check if NetworkManager is running or not

# nmcli -t -f RUNNING general
running

To get a general status

# nmcli general
STATE      CONNECTIVITY  WIFI-HW  WIFI     WWAN-HW  WWAN
connected  full          enabled  enabled  enabled  enabled

2. List all the available device

To view and list all the available devices on your Linux system

# nmcli dev status
DEVICE      TYPE      STATE         CONNECTION
eth0        ethernet  connected     eth0
virbr0      bridge    disconnected  --
eth1        ethernet  disconnected  --
eth2        ethernet  disconnected  --
lo          loopback  unmanaged     --
virbr0-nic  tun       unmanaged     --

3. List all the available connections

To list all the available connections

# nmcli con show
NAME  UUID                                  TYPE      DEVICE
eth1  01fa0bf4-b6bd-484f-a9a3-2b10ff701dcd  ethernet  eth1
eth0  2e9f0cdd-ea2f-4b63-b146-3b9a897c9e45  ethernet  eth0
eth2  186053d4-9369-4a4e-87b8-d1f9a419f985  ethernet  eth2

4. List all the configuration of interface

To view all the configured values (default and custom) of an interface

# nmcli con show eth2
connection.id:                          eth2
connection.uuid:                        186053d4-9369-4a4e-87b8-d1f9a419f985
connection.stable-id:                   --
connection.type:                        802-3-ethernet
connection.interface-name:              eth2
connection.autoconnect:                 yes

<Output trimmed>

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5. Check physical network device status

Now the status of all the connection network devices

# nmcli dev status
DEVICE  TYPE      STATE         CONNECTION
eth1    ethernet  connected     eth1
eth0    ethernet  connected     eth0
eth2    ethernet  disconnected  --
lo      loopback  unmanaged     --

6. Change hostname using nmcli

You can ideally change hostname using hostnamectl command, but you can also update hostname using nmcli

To get the current hostname

# nmcli general hostname
centos-8.example.com

Next to update the hostname

# nmcli general hostname  centos-8.golinuxcloud.com

Verify the same

# nmcli general hostname
centos-8.golinuxcloud.com

# hostname
centos-8.golinuxcloud.com

7. Create a new ethernet connection and assign static IP Address

In this example nmcli configures the eth2 interface statically, using the IPv4 address and network prefix 10.10.10.4/24 and default gateway 10.10.10.1, but still auto connects at
startup and saves its configuration into /etc/sysconfig/network-scripts/ifcfg-eth2 file.

# nmcli con add con-name eth2 type ethernet ifname eth2 ipv4.method manual ipv4.address 10.10.10.4/24 ipv4.gateway 10.10.10.1
Connection 'eth2' (460b16aa-e755-403e-b0ec-5e1560dcc441) successfully added.

8. Create a new ethernet connection and assign DHCP IP Address

The following command will add a new connection for the interface eth2, which will get IPv4 networking information using DHCP and will autoconnect on startup. The configuration will be
saved in /etc/sysconfig/network-scripts/ifcfg-eth2 because the con-name is eth2

# nmcli con add con-name eth2 type ethernet ifname eth2 ipv4.method auto
Connection 'eth2' (d75cb87f-cd15-40a2-9c33-138e69a06a1f) successfully added.

We can verify the same in the mapped interface configuration file

# egrep BOOTPROTO /etc/sysconfig/network-scripts/ifcfg-eth2
BOOTPROTO=dhcp

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9. Create and configure bond connection (active-backup) with two slave interface

You can create bond connection with multiple slave interface using nmcli.

Delete any configuration file which exists for slave interface

# nmcli con del "eth1"
# nmcli con del "Wired connection 1"

Add bond interface using nmcli. This command adds a master bond connection, naming the bonding interface mybond0 and using active-backup mode. I have given some dummy values for MII, UPDELAY and DOWNDELAY. If you wish to add primary interface using “primary=<ifname>”

# nmcli con add type bond ifname mybond0 bond.options "mode=active-backup,downdelay=5,miimon=100,updelay=10"
Connection 'bond-mybond0' (a5c76dbe-550b-4abf-8dc0-88184ade369e) successfully added.

Similarly for round-robin bonding you can use bond.options as “downdelay=5,miimon=100,mode=balance-rr,updelay=10”

Next add the slaves for mybond0 using nmcli. This command binds first slave to eth1 interface

# nmcli con add type ethernet ifname eth1 master mybond0
Connection 'bond-slave-eth1' (54dc4282-b90b-4469-9cbf-82bce042de85) successfully added.

This command binds slave 2 to eth2 interface

# nmcli con add type ethernet ifname eth2 master mybond0
Connection 'bond-slave-eth2' (41a5b4a6-8e6b-4df9-bff2-b67c5328311a) successfully added.

List the active connections. So we have our bond and slave interface with us.

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# nmcli con show
NAME             UUID                                  TYPE      DEVICE
bond-mybond0     25ce17b2-fffb-4bf1-a5a3-e7593299f303  bond      mybond0
bond-slave-eth1  54dc4282-b90b-4469-9cbf-82bce042de85  ethernet  eth1
bond-slave-eth2  41a5b4a6-8e6b-4df9-bff2-b67c5328311a  ethernet  eth2
eth0             d05aee6a-a069-4e55-9fe4-771ca3336db6  ethernet  eth0

Here I am setting static IP Address, NetMask, Gateway, DNS and DNS Search to mybond0 using nmcli

# nmcli con mod bond-mybond0 ipv4.method manual ipv4.address 10.10.10.8/24 ipv4.gateway 10.10.10.1 ipv4.dns 8.8.8.8 ipv4.dns-search example.com

NOTE:

To use DHCP IP, use ipv4.method auto and do not provide any IP Address related details in the above command

Verify your mybond0 configuration file

# egrep 'BOOTPROTO|IPADDR|PREFIX|GATEWAY|DNS' /etc/sysconfig/network-scripts/ifcfg-bond-mybond0
BOOTPROTO=none
IPADDR=10.10.10.8
PREFIX=24
GATEWAY=10.10.10.1
DNS1=8.8.8.8

refresh/reload the network configuration change for mybond0

# nmcli con up bond-mybond0
Connection successfully activated (master waiting for slaves) (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/11)

Verify the bond IP Address

# ip addr show mybond0
7: mybond0: &lt;BROADCAST,MULTICAST,MASTER,UP,LOWER_UP&gt; mtu 1500 qdisc noqueue state UP group default qlen 1000
    link/ether 08:00:27:0d:ca:0c brd ff:ff:ff:ff:ff:ff
    inet 10.10.10.8/24 brd 10.10.10.255 scope global noprefixroute mybond0
       valid_lft forever preferred_lft forever

Verify the list of available connection

# nmcli con show --active
NAME  UUID                                  TYPE      DEVICE
eth1  01fa0bf4-b6bd-484f-a9a3-2b10ff701dcd  ethernet  eth1
eth0  2e9f0cdd-ea2f-4b63-b146-3b9a897c9e45  ethernet  eth0

10. Create and configure Network Bridge

I have written another article with detailed steps to create and configure network bridge using nmcli and nmtui separately on RHEL/CentOS 7 and 8 Linux.

11. Create and configure Network Teaming

I have written another article with detailed steps to create and configure NIC teaming with two slaves using nmcli validated on RHEL/CentOS 7/8 Linux

12. Reload connection using nmcli (restart)

Reload all connection files from disk. NetworkManager does not monitor changes to connection files by default. So you need to use this command in order to tell NetworkManager to re-read the connection profiles from disk when a change was made to them.

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# nmcli con reload

13. Interactively add/edit a connection

You can use nmcli con edit to Edit an existing connection or add a new one, using an interactive editor. In the below example we will edit eth1’s IP Address

# nmcli con edit  eth1

===| nmcli interactive connection editor |===

Editing existing '802-3-ethernet' connection: 'eth1'

Type 'help' or '?' for available commands.
Type 'print' to show all the connection properties.
Type 'describe [.]' for detailed property description.

You may edit the following settings: connection, 802-3-ethernet (ethernet), 802-1x, dcb, sriov, ethtool, match, ipv4, ipv6, tc, proxy
nmcli&gt; help
------------------------------------------------------------------------------
---[ Main menu ]---
goto     [ | ]        :: go to a setting or property
remove   [.] |  :: remove setting or reset property value
set      [. ]  :: set property value
describe [.]          :: describe property
print    [all | [.]]  :: print the connection
verify   [all | fix]                 :: verify the connection
save     [persistent|temporary]      :: save the connection
activate [] [/|]    :: activate the connection
back                                 :: go one level up (back)
help/?   [<command></command>]                 :: print this help
nmcli            :: nmcli configuration
quit                                 :: exit nmcli
------------------------------------------------------------------------------
nmcli&gt; print ipv4.address
ipv4.addresses: 10.10.10.4/24
nmcli&gt; remove ipv4.address "10.10.10.4/24"
nmcli&gt; print ipv4.address
ipv4.addresses:
nmcli&gt; set ipv4.address 10.10.10.5/24
Do you also want to set 'ipv4.method' to 'manual'? [yes]: yes
nmcli&gt; print ipv4.address
ipv4.addresses: 10.10.10.5/24
nmcli&gt; verify
Verify connection: OK
nmcli&gt; save
Connection 'eth1' (7e3a1246-1743-4bb8-9eab-09664ab996b8) successfully updated.
nmcli&gt; quit

Now verify your changes in eth1’s configuration file

# egrep IPADDR /etc/sysconfig/network-scripts/ifcfg-eth1
IPADDR=10.10.10.5

14. Change ethernet connection BOOTPROTO from DHCP to Static

Now to change ethernet connection BOOTPROTO from DHCP to static using nmcli, we must modify ipv4.method directive to use manual

# nmcli con mod eth2 ipv4.method manual ipv4.address 10.10.10.4/24 ipv4.gateway 10.10.10.1

Now verify the network configuration file for eth2

# egrep 'BOOTPROTO|IPADDR|PREFIX|GATEWAY' /etc/sysconfig/network-scripts/ifcfg-eth2
BOOTPROTO=none
IPADDR=10.10.10.4
PREFIX=24
GATEWAY=10.10.10.1

15. Change ethernet connection BOOTPROTO from Static to DHCP

Similarly to change ethernet connection BOOTPROTO from static to DHCP using nmcli, we must modify ipv4.method directive to use auto

# nmcli con mod eth2 ipv4.method auto

Now verify the eth2 network configuration file

# egrep 'BOOTPROTO|IPADDR|PREFIX|GATEWAY' /etc/sysconfig/network-scripts/ifcfg-eth2
BOOTPROTO=dhcp
IPADDR=10.10.10.4
PREFIX=24
GATEWAY=10.10.10.1

As you see we still have IPADDR and other variables from previous command but they are considered null, because you can see my DHCP has assigned 10.10.10.5 to eth2

# ip addr show dev eth2
4: eth2: &lt;BROADCAST,MULTICAST,UP,LOWER_UP&gt; mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 08:00:27:a8:19:0a brd ff:ff:ff:ff:ff:ff
    inet 10.10.10.5/24 brd 10.10.10.255 scope global noprefixroute dynamic eth2
       valid_lft 1068sec preferred_lft 1068sec
    inet6 fe80::b81f:a58b:43f1:b8d3/64 scope link noprefixroute
       valid_lft forever preferred_lft forever

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16. Change ONBOOT directive using nmcli

By default ONBOOT is yes in the interface configuration file. So to disable ONBOOT we must modify connection.autoconnect directive using nmcli

Verify the ONBOOT value before changing this directive

# egrep 'ONBOOT' /etc/sysconfig/network-scripts/ifcfg-eth2
ONBOOT=yes

Change ONBOOT directive, disable ONBOOT using nmcli

# nmcli con mod eth2 connection.autoconnect no

Re-verify the ONBOOT directive for eth2

# egrep 'ONBOOT' /etc/sysconfig/network-scripts/ifcfg-eth2
ONBOOT=no

17. Change DEFROUTE directive (Never use this network for default route)

By default any gateway we add for any ethernet connection will also be considered as default gateway, to turn off this directive use ipv4.never-default with nmcli

Before we make any change verify DEFROUTE directive in the eth2 configuration file

# egrep '^DEFROUTE' /etc/sysconfig/network-scripts/ifcfg-eth2
DEFROUTE=yes

So by default this directive is ON, we will disable the default gateway option for eth2. To turn off this directive we must select ipv4.never-default as “yes”

# nmcli con mod eth2 ipv4.never-default yes

Next verify the DEFROUTE directive for eth2

# egrep '^DEFROUTE' /etc/sysconfig/network-scripts/ifcfg-eth2
DEFROUTE=no

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18. Disable IPv6 Address for ethernet connection (IPV6INIT)

By default both IPv4 and IPv6 connection type (IPV6INIT) is enabled for any ethernet connection type. To only use IPv4 and disable IPv6 using nmcli

Verify the existing status of IPv6 connection type for eth2

# egrep  'IPV6INIT' /etc/sysconfig/network-scripts/ifcfg-eth2
IPV6INIT=yes

So this is enabled, we will disable IPv6 connection type using ipv6.method directive with nmcli

# nmcli con mod eth2 ipv6.method ignore

Now re-verify the IPV6INIT directive from eth2 config file

# egrep  'IPV6INIT' /etc/sysconfig/network-scripts/ifcfg-eth2
IPV6INIT=no

19. Change “Automatically Connect” Directive

By default any ethernet connection will be allowed to automatically connect, you can modify this using

# nmcli con mod eth2 connection.autoconnect no

20. Add or Modify DNS to existing connection

You can use ipv4.dns to add DNS server to an new connection or modify any existing connection using nmcli.
Currently there are no DNS server IP provided for eth1

# egrep DNS /etc/sysconfig/network-scripts/ifcfg-eth1

Next modify connection to add DNS Server IP Address

# nmcli con mod eth1 ipv4.dns 8.8.8.8

Verify the eth1 config file

[root@rhel-8 ~]# egrep DNS /etc/sysconfig/network-scripts/ifcfg-eth1
DNS1=8.8.8.8

21. Append single/multiple DNS Server to connection

Use + prefix with ipv4.dns to append new DNS IP Addresses to an existing connection using nmcli. In the previous example we added 8.8.8.8 as my DNS server for eth1. Now we will append 8.2.2.2 to the same connection

# nmcli con mod eth1 +ipv4.dns 8.2.2.2

Verify the eth1 configuration file

# egrep DNS /etc/sysconfig/network-scripts/ifcfg-eth1
DNS1=8.8.8.8
DNS2=8.2.2.2

22. Remove single/multiple DNS Server from connection

As it is understood, with + we append so with – we remove single/multiple entries of DNS Server from the interface connection using nmcli.

# nmcli con mod eth1 -ipv4.dns 8.2.2.2,8.8.8.8

Verify the eth1 configuration file

# egrep DNS /etc/sysconfig/network-scripts/ifcfg-eth1

23. Display selected fields with values of connection

You can list all the configured values of a connection using “nmcli con show <ifname>” but that gives you a long list of details, you can actually also get selected value of the provided directive of an individual connection

To get the IPv4 Address of eth1

# nmcli -g ip4.address connection show eth1
10.10.10.4/24

You can use -g to print values from specific fields using nmcli

# nmcli -g ip4.address,ipv4.dns connection show eth1
8.8.8.8,8.2.2.2
10.10.10.4/24

But here as you see we do not get a field to value mapping. You can use -f to specify what fields (column names) should be printed using nmcli. Valid field names differ for specific commands. List available fields by providing an invalid value to the --fields option.

# nmcli -f ipv4.dns,ipv4.addresses,ipv4.gateway con show eth1
ipv4.dns:                               8.8.8.8,8.2.2.2
ipv4.addresses:                         10.10.10.4/24
ipv4.gateway:                           10.10.10.1

24. Monitor connection and device activity

Using nmcli monitor you can observe NetworkManager activity. Watches for changes in connectivity state, devices or connection profiles. Here in this example we will execute nmcli monitor for eth1 in one terminal, and on the other terminal we will make some modification to eth1 connection

# nmcli con mod eth1 ipv4.method manual ipv4.address 10.10.10.4/24

As you see, after the modification, the monitor command gives below output

# nmcli con monitor eth1
eth1: connection profile changed

25. Activate a connection

Just opposite to what we used above, we will use nmcli con up

# nmcli con up eth2
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/23)

Verify the list of available connection

# nmcli con show --active
NAME  UUID                                  TYPE      DEVICE
eth1  01fa0bf4-b6bd-484f-a9a3-2b10ff701dcd  ethernet  eth1
eth0  2e9f0cdd-ea2f-4b63-b146-3b9a897c9e45  ethernet  eth0
eth2  186053d4-9369-4a4e-87b8-d1f9a419f985  ethernet  eth2

26. De-activate a connection

Deactivate a connection from a device without preventing the device from further auto-activation using nmcli con down <ifname>. Multiple connections can be passed to the command.

# nmcli con down eth1
Connection 'eth1' successfully deactivated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/32)

Verify the list of active connections

# nmcli con show --active
NAME  UUID                                  TYPE      DEVICE
eth0  d05aee6a-a069-4e55-9fe4-771ca3336db6  ethernet  eth0

NOTE:

If you are connected to your server using this interface then your connection would close once the connection is de-activated

27. Delete connection

lastly in nmcli command examples, you can delete all type of available connection using “nmcli con del <ifname>”

# nmcli con del bond-mybond0 bond-slave-eth1 bond-slave-eth2
Connection 'bond-mybond0' (25ce17b2-fffb-4bf1-a5a3-e7593299f303) successfully deleted.
Connection 'bond-slave-eth1' (54dc4282-b90b-4469-9cbf-82bce042de85) successfully deleted.
Connection 'bond-slave-eth2' (41a5b4a6-8e6b-4df9-bff2-b67c5328311a) successfully deleted.

Lastly I hope the steps from the article with nmcli command examples (cheatsheet) on Linux was helpful. So, let me know your suggestions and feedback using the comment section.

References:

golinuxcloud.com
man page nmcli
man page nmcli-examples

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CISCO ASA – %ASA-6-722036 Transmitting large packet 1418 (threshold 1347) https://www.f1-consult.com/cisco/cisco-security/asa/transmitting-large-packet/ Fri, 05 Feb 2021 10:55:37 +0000 https://www.f1-consult.com/?p=4686

Problem:

On ASA syslog you seen the Anyconnect warning message

%ASA-6-722036: Group <ac_users_group> User <vpn> IP <> Transmitting large packet 1418 (threshold 1347)

Solution:

!
sysopt conn tcpmss 1460
!
group-policy DfltGrpPolicy attributes 
webvpn
anyconnect mtu 1300
anyconnect ssl df-bit-ignore enable
!

In order to eliminate this visible transition of DTLS > TLS,  the administrator can configure a separate tunnel group for TLS only access for users that have trouble with the establishment of the DTLS tunnel (such as due to firewall restrictions).

  1. The best option is to set the AnyConnect MTU value to be lower than the TLS MTU, which is then negotiated.

group-policy ac_users_group attributes
webvpn
anyconnect mtu 1300

This makes TLS and DTLS MTU values equal. Reconnections are not seen in this case.

  1. The second option is to allow fragmentation.

group-policy ac_users_group attributes
webvpn
anyconnect ssl df-bit-ignore enable

With fragmentation, large packets (whose size exceeds the MTU value) can be fragmented and sent through the TLS tunnel.

  1. The third option is to set the Maximum Segment Size (MSS) to 1460 as follows:

sysopt conn tcpmss 1460

In this case, the TLS MTU will be 1427 (RC4/SHA1) which is larger than the DTLS MTU 1418 (AES/SHA1/LZS). This should resolve the issue with TCP from the ASA to the AnyConnect client (thanks to MSS), but large UDP traffic from the ASA to the AnyConnect client might suffer from this as it will be dropped by the AnyConnect client due to the lower AnyConnect client MTU 1418. If sysopt conn tcpmss is modified, it might affect other features such as LAN-to-LAN (L2L) IPSec VPN tunnels.

Reference:

https://community.cisco.com/t5/vpn/anyconnect-issue/td-p/2708533

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CISCO IOS XE – passwords will soon be deprecated https://www.f1-consult.com/cisco/ios-xe/password-deprecated/ Fri, 25 Dec 2020 13:25:54 +0000 https://www.f1-consult.com/?p=4631
CISCO IOS-XE warning

WARNING: Command has been added to the configuration using a type 5 password. However, type 5 passwords will soon be deprecated. Migrate to a supported password type

WARNING: Command has been added to the configuration using a type 7 password. However, type 7 passwords will soon be deprecated. Migrate to a supported password type

What it says is this: At some point in the future, IOS-XE won’t store plaintext passwords in running-config or startup-config anymore. It will only store hashed passwords (for authentication purposes when the knowledge of the password plaintext isn’t needed anymore) and securely encrypted passwords (for those passwords whose original plaintext still needs to be recoverable).

Secure encrypted passwords, also known as Type-6 passwords, can be enabled on the device using the following commands:

!
conf t
 configure terminal
 key config-key password-encryption
 password encryption aes
end
!

The key config-key password-encryption command will prompt you for a master key that will subsequently be used to encrypt all passwords in the configuration where this encryption is supported, including TACACS+ keys. The encryption of these passwords will be the enabled using the password encryption aes command – without this command, the master key may be configured but will not be used to protect the passwords in the configuration.
This is described in a couple of documents out there,
including https://www.cisco.com/c/en/us/support/docs/security-vpn/ipsec-negotiation-ike-protocols/46420-pre-sh-keys-ios-rtr-cfg.html

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CentOS – Installer just goes black screen on Centos8 https://www.f1-consult.com/linux/centos-blackscreen/ Thu, 25 Jun 2020 20:38:28 +0000 https://www.f1-consult.com/?p=4609 Problem:

During installation of CentOS the installer screen goes black.

  • The terminal multiplexer is running in virtual console 1.
  • To switch from the graphical installation environment to tmux, press Ctrl+Alt+F1.
  • To go back to the main installation interface which runs in virtual console 6, press Ctrl+Alt+F6.

Available tmux Windows

Shortcut Contents
Ctrl+b 1 Main installation program window. Contains text-based prompts (during text mode installation or if you use VNC Direct Mode), and also some debugging information.
Ctrl+b 2 Interactive shell prompt with root privileges.
Ctrl+b 3 Installation log; displays messages stored in /tmp/anaconda.log.
Ctrl+b 4 Storage log; displays messages related storage devices from kernel and system services, stored in /tmp/storage.log.
Ctrl+b 5 Program log; displays messages from other system utilities, stored in /tmp/program.log.

Switching to Terminal Ctrl+Alt+F1 you see

  • X startup failed, falling back to text mode
  • Pane is dead (signal 10)

Solution:

  • install system with basic video driver
  • install in text mode by adding "inst.text" to the end of the GRUB boot line
  • Press ENTER to continue with the normal boot.
  • Make selection from the above menu. Perform configuration and return back to the main menu by pressing the c key. Once ready begin the RHEL 8 installation by pressing the b key.
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