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 ARP table to this …
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 0/0/0 transceiver status # show hw-module interface tenGigabitEthernet 0/0/0 transceiver idprom .. to be continued
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 CEST: Vi4 …
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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 configureable and working, …
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 …
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-register was set to 0x2101 right out of …
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 into the routing table. The routing engine uses an “administrative distance” per routing protocol to …
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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: I found one difference between CSS and non-CSS connects: the TCP WSCALE option. When the …
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 Cisco’s IP phone software releases 8.3(3) or higher according to Cisco bug id: CSCso40588. Cisco …
Problem: Windows NLB IPs are are not reachable through and from Cisco routers and switches. NLB services could be IIS arrays, Exchange CAS arrays, etc. Solution: NLB mode was set to Multicast. In this mode Windows incorrectly uses multicast mac addresses. Set the NLB mode to Unicast and configure static mac address table entries on …
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