Networking Blog

Recently i stumbled across a nice feature in Cisco IOS for building customized menus.
The “menu”-command is really old and was introduced in IOS 10.0
You can i.e. use it for building a menu for CLI-unexperienced staff to simplify troubleshooting.
First of all, you have to configure a little bit AAA  as well as create a user with [...]

Solaris Network configuration is a little bit different to Debian.
Because i always forget it, there’s a quick explanation of the necessary steps (taken from here and used with Solaris 5,6,7,8 +9).
/etc-Files
All configuration data, such as IP addresses, gateways, and so on, can be defined and changed at runtime level.
But first of all you have to [...]

Sometimes, it’s necessary to capture packets with tcpdump on a machine without running X-Windows installation.
But most people are not such  cracks, that they can read the confusing output on the console (me included).
To get a better overview, i prefer Wireshark (former known as Ethereal).
With the following tcpdump-flags, you can create a file in .pcap format [...]

When Access Control List Logging is activated on your Cisco device, you will see log entries like that in syslog:

Jun 14 09:49:13 RTR-1 41716: Jun 14 09:49:12.148 MEZ: %SEC-6-IPACCESSLOGP: list 120 denied udp x.x.x.x(1670) -> x.x.x.x(4808), 1 packet
Jun 16 22:14:09 RTR-1 42271: Jun 16 22:14:08.847 MEZ: %SEC-6-IPACCESSLOGDP: list 125 denied icmp x.x.x.x -> x.x.x.x (0/0), [...]

When you deal with Cisco and BGP, you probably know syslog messages like this:

Apr 11 16:34:38 ROUTER 1026843: Apr 11 16:34:38.010 CET: %BGP-3-NOTIFICATION: received from neighbor 80.x.x.x 6/2 (cease) 0 bytes
Apr 17 14:13:41 ROUTER 30082: Apr 17 14:13:41.126 CET: %BGP-3-NOTIFICATION: received from neighbor 80.x.x.x 6/0 (cease) 0 bytes
Apr 27 05:30:39 ROUTER 1028828: Apr 27 05:30:39.833 [...]