Route filtering methods in EIGRP

When you use EIGRP as routing protocol, you have two options for filtering advertised routes:

distribute-lists
redistribute-statement with route-map

Received networks can only be filtered out with

distribute-lists

In my simple example, there are 2 routers (R1 and R2) connected via FastEthernet0/1.
Both routers are running EIGRP process 123.

Creating EIGRP process 123 on both routers
With the default configuration, only the link-net [...]

Cisco banner usage

In Cisco IOS, you can use several methods of banners.
The most common methods are:

banner exec
banner login
banner motd

Though all commands use the same syntax
banner motd|login|exec <delimiter> <banner text> <delimiter>
! delimiter is a character, that must not exist in
! the banner message.
there is a different behaviour according to the login method used.
Here’s a table, which shows [...]

Bridging Ethernet over an IP network using DLSw+

While surfing through the internet, i found a nice feature called DLSw+. I must admit, that i never heard about it before, although it’s a really old feature.
DLSw (Data Link Switching) originally was developed to transport IBM Systems Network Architecture (SNA) and IBM NetBIOS over routed IP networks. But you can also use it for [...]

Bridging across GRE tunnels (experimental)

In former posts, i already mentioned the flexibility of GRE tunnels.
A few days ago, i tried to assign a Tunnel interfaces to a bridge-group to get Layer-2 conectivity between 2 sites.
Unexpectedly, it works, although bridge-group commands aren’t supported on Tunnel interfaces.
Here`s a small image, to illustrate the setup

The setup in this example is using  c3725-adventerprisek9-mz.124-15.T6.bin [...]

PPPoE dialin with a Cisco 871/876/878

The Cisco 871/876 is a small SOHO router with an integrated four-port switch on the LAN side.
On the WAN side, the C871 provides a Fastethernet interface for connecting an external xDSL-Modem, while C876/C878 have integrated xDSL-Modems available. C876 provides the ADSL Annex B flavor, the C878 offers an SHDSL-Modem.
Here are two templates for PPPoE dialin to an ISP.
Traffic from internal LAN is natted [...]

Configuring a Multichannel STM-1 on a Cisco router

When you have numerous E1 customers (> 8), you could terminate them on dedicated E1 ports of a router, e.g. with one or more  PA-MC-8E1/120 (EoL since 2003).
A more efficient way is to terminate them on a STM-1 port-adapter (e.g. a PA-MC-STM1), where you can aggregate up to 63 customers with one single fiber connection to the transport [...]

Setting up a Cisco router for terminating Microsoft L2TP IPSec sessions

 
For this example i used a Cisco 1841 running c1841-advsecurityk9-mz.124-3i.bin

Remote User connects to gate’s puplic reachable IP with his Microsoft L2TP IPSec client (Windows 2000 and higher)
After successful authentication, the Client gets an IP address from local pool
MS L2TP-IPSec-Client adds a default route over the new PPP interface (but you can deactivate it)

Here’s the template for router [...]

The Cisco IOS archive command

As i mentioned in another post, i use RANCID for fetching and diffing router/switch configurations.
But when you need an quick and easy solution without CVS backend, you could try the IOS archive command.
Certainly, it is not as comfortable as other tools and has the restriction to save only 14 archive files, but it’s still better than nothing.
It [...]

Setting up a Cisco router for terminating Microsoft PPTP sessions

 
For this example i used a Cisco 1841 running c1841-advsecurityk9-mz.124-3i.bin
Explanation:

Remote User connects to gate’s puplic reachable IP with his Microsoft PPTP client (Windows 2000 or higher)
After successful authentication, the Client gets an IP address from local pool
MS PPTP-Client adds a default route over the new PPP interface (but you can deactivate it)

 Here’s the configuration template

aaa new-model
aaa authentication ppp [...]

Using EIGRP with IPSEC encrypted GRE tunnels

In one of my last posts, GRE tunneling with IPSec encryption, i explained the setup of a simple ipsec-protected GRE connection.
When your network is a little bit larger than my test scenario, you would prefer to use an dynamic routing protocol between your routers (hilde and maria in my case).
Nothing easier than that….
Here’s an example using [...]