[cisco-voip] Unusual UCOS installation condition - sanity check please

Ryan Huff ryanhuff at outlook.com
Sun Mar 20 11:55:31 EDT 2016

Encountering the duplicate ip on eth0 installation error for UCOS. The IP is not actually duplicated on the segment though.

My experience with this error is that it is usually right; in the sense that something is not compatible with UCOS in the network. What I'm not certain of, is what method the installer uses to determine the duplicate condition. I believe the installer is using an ARP ping to determine if there is a dup condition. The error comes on a subscriber, right after the validation to first node check.

I believe the network may be using Proxy ARP (not completely sure); which to my knowledge, won't work with UCOS. I don't have visibility/access into the network but I do need to be able to articulate why the installer detects a dup IP (when there really isn't a dup IP). I have quadruple verified I am using the right first node / security password. This is happening for multiple subscriber nodes too (same segment), so I'm confident it is network related, not fat-finger related.

Here is the Scenario:

  *   CUCM 10.5.2 cluster over WAN (not sure what the WAN link is)
  *   2 sites; SITE_A and SITE_B (not sure what infrastructure gear is at each site)
     *   SITE_A: pub&sub
     *   SITE_B: sub

In SITE_A, the pub&sub install without issue. In SITE_B, right after the sub installer does the validation to first node check, it pops the duplicate ip error. I have a linux server installed on the SITE_A and SITE_B segment.

>From the SITE_A linux server, I do an ARPing to the SITE_B IP addresses and I get the MAC address for the SITE_A WAN router (Cisco OID). From the SITE_B linux server, I do an ARPing to the SITE_A IP addresses and I get the MAC address for the SITE_B WAN router (Cisco OID).

Anyone have any thoughts into this?


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