Articles tagged with cisco ios

1. CEF memory leak in BWG

   Posted on August 15, 2011 in Networking

   For those still using the Cisco BWG as the ASN gateway in their WiMAX networks, Juda Barnes has discovered that the BWG 2.0 software suffers from a memory leak related to CEF. This memory leak is detailed in Cisco Bug CSCta09049. Unfortunately, since the Cisco BWG software has reached …

2. Cisco Break Sequence for Outgoing Telnet and SSH Sessions

   Posted on August 17, 2009 in Networking

   There are a few network devices out there that allow you to connect, but don't give you an option to disconnect. For example, you might be stuck at a password prompt, but have no authentication details. Most telnet clients allow you to break these connections with the ^] (control-]) command. <acronym …

3. Cisco Catalyst 12.2(46)SE May Break SNMP ifIndexes

   Posted on September 10, 2008 in Networking

   This week I tried upgrading a Cisco Catalyst 2960 to the newest software release — 12.2(46)SE. The upgrade went just fine, but I noticed that the monitoring software was throwing SNMP errors.

   In case you don't know much about SNMP, an ifIndex identifies a specific interface on a …

4. How to Check Power Supply Status on Cisco Switches and Routers

   Posted on July 25, 2007 in Networking

   When a Cisco switch or router reports a power problem, start by finding out whether the issue is input power, a failed supply, redundancy, PoE budget, or a sensor alarm. Those are related, but they are not the same failure.

   For most Cisco IOS and IOS XE platforms, this is …

5. Cisco, NAT, and Port Range Stupidity

   Posted on July 19, 2007 in Networking

   Anyone who has ever done anything remotely "interesting" with a run-of-the-mill broadband router is undoubtedly familiar with the concept of port forwarding. In the case of some applications (<acronym title="Peer-to-Peer">P2P</acronym> comes immediately to mind, but the <acronym title="Real-time Transport Protocol">RTP</acronym> part of <acronym title …

6. Use Scheduled Reloads to Safely Make Remote Cisco Changes

   Posted on July 09, 2007 in Networking

   A remote network change becomes an outage when the change breaks the only path back to the device. It does not matter whether the mistake is a bad ACL, an incorrect default route, an interface change, or an authentication policy that locks out your SSH session. If you have no …

7. The Annoyance of 'show config'

   Posted on June 11, 2007 in Networking

   How many times has this happened to you?

   SLAP#write memory
   startup-config file open failed (Device or resource busy)
   

   If you work in an environment where multiple users have enable access on Cisco devices, you've probably seen it more than once. This particular error is caused when another user has …

8. Implement a Sensible Naming Policy in Cisco IOS

   Posted on April 10, 2007 in Networking

   Network configuration names are not decoration. They are operational metadata. When something is broken at 2:00 a.m., the difference between ACL-EDGE-IN and access-list is not aesthetic. It is the difference between narrowing the blast radius quickly and spelunking through hundreds or thousands of lines of Cisco IOS configuration …