Posts tagged "Cisco"
Cisco "Smart" License
Problem: after upgrading Cisco ISO XE from 15 to 16 on an ASR-1001-X router, the permanent license of this router changes to "evaluation license" and Cisco forces you to use the call-home "feature". You will find log entries like these: *Jan 23 21:53:13.922: %SMART_LIC-6-AGENT_ENABLED: Smart Agent for Licensing is e...
Interface down on Cisco Nexus switch with "dcxNoACKi"
Problem: After an update of a server to Devuan4/Debian11the switch shuts down the interfaces to the server with status "dcxNoACKi" 48 minutes after the reboot. Discussion: the switch is a Cisco Nexus 5000 switch. It implements "Data Center Bridging Capability Exchange (DCBX)". The server is a Dell server with X710 C...
Cisco Serial Number Production Date
Every Cisco switch has a serial number that shows information about it's production location and year. SW# show version Cisco IOS Software, C3560 Software (C3560-IPBASE-M), Version 12.2(35)SE5, RELEASE SOFTWARE (fc1) Copyright (c) 1986-2007 by Cisco Systems, Inc. Compiled Thu 19-Jul-07 18:15 by nachen Image text-bas...
Cisco ASR-1001-X Update
There are at least two pieces of software you can update in a Cisco ASR-1001-X. The ROMMON (firmware) and the IOS itself. This router uses "Cisco IOS XE Software". Which is an IOS process on a Linux kernel as far as I know. Cisco recommends specific ROMMON releases for different generations of software. You can look...
ARP is not working on Cisco ASR 1001 X
Problem: Cisco ASR router is loosing connectivity to its directly attached Ethernet neighbors. In this situation interface status is still up, packets are going in and out on both ends, even IPv6 was still working. The actual problem was that the Cisco ASR was ignoring all ARP responses from its neighbors and the AR...
ASR Tips'n'Tricks
ASR-1001-X and IOS-XE is sometimes different and sometimes very similar to classic IOS. Update. You can update, the firmware as usual: # copy http: bootflash: # conf t (config)# boot system flash bootflash:asr1001x-universalk9.03.16.00.S.155-3.S-ext.SPA.bin Show SFP (transceiver) info: # show hw-module interface ten...
MLPPP over L2TP over Ethernet Channel Groups on Cisco ASR
Problem: After upgrading an ethernet port to a channel-group, all MLPPP connections fail on a Cisco ASR 1002-X. The log file looks like this: Jul 31 2015 07:04:44.801 CEST: Vi4 PPP: Phase is AUTHENTICATING, Authenticated User Jul 31 2015 07:04:44.801 CEST: Vi4 CHAP: O SUCCESS id 143 len 4 Jul 31 2015 07:04:44.801 CE...
Cisco ASR 1002-X and PPTP
Problem: PPTP from any client to an ASR1002-X Cisco does not work. PPTP Connections starts but in PPP LCP phase the connection fails. Solution: Cisco ASR1002-X with Software IOS-XE 15.3(2)S2 has no PPTP support. You have to take a different Router! Discussion: The weird thing is, that most of the PPTP stack is still...
CDP / LLDP Fun
Problem: You want to know which switch and what port your Linux machine is connected to? Solution: If the switch does CDP (all Cisco switches do), it tells you a lot of information. Tcpdump can capture and show this information. # tcpdump -i eth0 -n -v -s 1500 -c 1 'ether[20:2] == 8192' tcpdump: listening on eth0, l...
Update Cisco Catalyst Software
I had to update the software of a new Cisco Catalyst 4948 yesterday. As usual I did: copy tftp://<hostname>/<filename> bootflash: conf t boot system flash bootflash:<filename> exit reload But the switch ignored the new software image. During boot it said: Booting first image from bootflash Solution: The config-regis...