Duplicate router ID?

[jkeeffe]

I have a duplicate router ID problem that is confusing to me.  A 6509 and 4510 swich both show the same router ID, but only the 6500 has the router ID IP address configured in it. We are running EIGPR.  The 6509 has L0 as 164.72.239.1 configured, which is it's router ID. The 4510 doesn't have 164.72.239.1 configured on it, yet that's what it's router ID is.  Below are a few show commands displaying this - and as you can see from the 'show run | include 239' from the 4510 there is no 164.72.239.1 configured on it:

6509 chassis

interface Loopback0
ip address 164.72.239.1 255.255.255.255
end

RS6509-Core-A#sh ip eigrp top
IP-EIGRP Topology Table for AS(1)/ID(164.72.239.1)

Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
       r - reply Status, s - sia Status

------------------------------------------------------------------------------------------------

4510 chassis

RS4510RE-AU-MDF#sh run | include 239
ip address 164.72.239.57 255.255.255.255
ip pim rp-address 164.72.239.42
FAC-RS4510RE-AU-MDF#
FAC-RS4510RE-AU-MDF#
FAC-RS4510RE-AU-MDF#sh ip eigrp top
EIGRP-IPv4 Topology Table for AS(1)/ID(164.72.239.1)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
       r - reply Status, s - sia Status

Any idea why the 4510 has that router ID?

I know I can configure a different router ID on the 4510, but I'm curious as to why it is the way it is.

[Edison Ortiz]

Perhaps it was configured in the 4500 chassis under Loopback 0 when the EIGRP process started and changed afterwards?

[jkeeffe]

That is possible - I didn't configure the box.  Is a reboot require to clear that out?

[Edison Ortiz · Accepted solution]

You can configure eigrp router-id 164.72.239.57 under the eigrp routing process to override the current dynamic router-id in the 4500