Route descriptions in Cisco IOS

Recently, i came accross the name keyword in the ip route command in Cisco IOS.
The CLI help is quite misleading:

router(config)# ip route ?
  <1-255>    Distance metric for this route
  name       Specify name of the next hop
  permanent  permanent route
  tag        Set tag for this route
  track      Install route depending on tracked item

PPPoE Dial-In with ASA5505

If you like to connect your external interface to the internet by using PPPoE, you have to configure a VPDN group first. In this simple example, our group is called PPPOE and we use PAP method for authentication. Unlike IOS, ASA OS accepts only one autentication protocol. Hence you have to know, if your provider [...]

Using two HWIC-4ESW in a Cisco 1841

Recently, there was a need for additional FastEthernet ports on a Cisco 1841. The router had already one  HWIC-4ESW attached, but all ports were occupied.
Fortunately, there was a second HWIC-4ESW at stock which was inserted immediately. Two additional ports was configured quickly to a vlan already in use on the other HWIC.
But then the problem [...]

Configuring Resilient Ethernet Protocol

Resilient Ethernet Protocol (REP) is a Cisco propietary protocol which allows you to build redundant Ethernet rings. It’s an alternative to Spanning-Tree protocol and also avoids bridging loops or responds to link failures.
Compared to STP, it offers a faster convergence time (< 300ms) and gives you a simple VLAN load-balancing method.
In our example, we interconnect [...]

Interface range macro

I often use the feature interface-range on Cisco switches running IOS.
Not so long ago, i discovered the command interface-range macro, from which i never heard before.
With this macro, you can visit group several interfaces together and address them by a significant name.
Short example:

define interface-range UPLINKS FastEthernet0/1, FastEthernet0/24
define interface-range USERPORTS FastEthernet0/2 - 23


switch#conf t
switch(config)#interface range macro [...]

Building a customized menu

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 [...]

ACL log identifiers

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), [...]

BGP Cease Subcode definition

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 [...]

Added new Page - IOS and JunOS commands

Just now, i added a new sticky page to my blog.
It’s a small comparison between Cisco IOS and Juniper JunOS CLI commands.
See here…

MTU difference between Cisco and Juniper

(Information taken from j-nsp mailing list and vendors homepages)
MTU Juniper
NOTE: The actual frames transmitted also contain cyclic redundancy check (CRC) bits, which are not part of the media MTU. For example, the media MTU for a Gigabit Ethernet interface is specified as 1500 bytes, but the largest possible frame size is actually 1504 bytes; you [...]