Category Archives: Cisco

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 … Continue reading

Posted in Cisco | Tagged , , , , | Leave a comment

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 … Continue reading

Posted in Cisco, Routing | Tagged , , , | Leave a comment

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 tenGigabitEthernet … Continue reading

Posted in Cisco, Routing | Tagged , | Comments Off on ASR Tips’n’Tricks

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 … Continue reading

Posted in Cisco, Routing | Tagged , , | Leave a comment

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! … Continue reading

Posted in Cisco, Routing | Tagged , , , , | Comments Off on Cisco ASR 1002-X and PPTP

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. … Continue reading

Posted in Cisco, Linux | Tagged , , | Comments Off on CDP / LLDP Fun

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: … Continue reading

Posted in Cisco, Internet, Routing | Tagged , , , | Leave a comment

Cisco Routing – Administrative Distance

Cisco routers are capable of different routing protocols and static and connected routes. Every routing protocol engine has its own distance/metric/weight to decide which route is best. When a routing protocol has chosen its best route, the route is entered … Continue reading

Posted in Cisco, Routing | Tagged , | Comments Off on Cisco Routing – Administrative Distance

WScale and Cisco Content Switch CSS.

Problem: Windows 7 clients wait 5 seconds to send simple HTTP requests to a web server behind a cisco CSS content switch. But there is no delay when the client connects directly to a web server behind the CSS. Description: … Continue reading

Posted in Cisco, Windows | Tagged , , , , | Comments Off on WScale and Cisco Content Switch CSS.

Cisco IP Phone and NTP

Problem: A Cisco IP phone (in my case 7970G) does not sync with an NTP server. The phone sends an NTP request, receives an NTP response, but does not set its date and time. Solution: It’s a known bug of … Continue reading

Posted in Cisco | Tagged , | Leave a comment