Cannot set ip authentication mode eigrp on 3750 switch running ipservicesk9-mz.122-55.SE8

[keithsauer507]

I am trying to configure EIGRP authentication on a Cisco 3750 switch following version:

System image file is "flash:/c3750-ipservicesk9-mz.122-55.SE8.bin"

I can create the key chain without an issue, but when I go into an interface Fa1/0/12 for example, it will not accept the command

ip authentication mode eigrp 100 md5

Is it ok to put this on a vlan interface tied to a switchport instead?  This seems to take...

int vlan1

ip authentication mode eigrp 100 md5

ip authentication key-chain eigrp 100 <keyname>

So if a router is connected to a port in vlan 1 in this example, and they are using the same md5 & key, eigrp should communicate between the two?

This is not production, this is a test for future implementation where a site is just using 3750x2's in layer 3 mode (they don't have an onsite router) and they are going from a simple 1 WAN connection (with a static quad 0 route) to a 2 WAN connection (for backup) and eigrp proposed to handle picking the routes.

[acampbell · Accepted solution]

Hi,

From the config guide

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750/software/release/12-2_55_se/configuration/guide/scg3750/swiprout.html#wp1051432

You can configure the "ip authentication mode eigrp 100 md5" on any layer 3 interface.

So yes you can use interface vlan

or

interface fast 1/0/12 only if this has been set as a layer 3 port ie// "no switchport"

Regards

Alex

[keithsauer507]

Perfect!!!

I forgot no switchport on that interface.  Yes now I can apply it there, or apply it at the vlan level.