How to verify the Cisco Jabber DNS SRV configuration?

[Muthurani Lavanya Paneerselvam]

Introduction

This document explains how to verify the Cisco Jabber DNS SRV configuration.

How to verify the Cisco Jabber DNS SRV configuration?

"NSLOOKUP" can be used to verify that the SRV records are correctly configured. This is particular important in environment where DNS configuration
is handled by different organizational entities. Best use the NSLOOKUP from one of the Windows 7 PC to verify they can correctly resolve the SRV.

By default, the NSLOOKUP tool queries either DNS A records - mapping a name to an IP address or PTR records mapping IP address to DNS names. To use the tool to check SRV records,

First start nslookup (on a windows client ) start the command prompt and then enter nslookup

Next set the query type to SRV -> set type = SRV

After that insert the SRV record we need to check -> _cisco-uds._tcp.example.com

This will return the DNS A records pointing to the CUCM servers.

The following is an example of the _cisco-uds SRV record:
_cisco-uds._tcp.example.com SRV service location:
priority = 6
weight = 30
port = 8443
svr hostname = cucm3.example.com

_cisco-uds._tcp.example.com SRV service location:
priority = 2
weight = 20
port = 8443
svr hostname = cucm2.example.com

Related Information

• Cisco Jabber DNS configuration guide

[Stephanie Knoop]

Additionally, if you need to confirm external DNS SRV records:

- In case your organization blocks these ports, be sure you are not on the corporate network/VPN

- After entering the nslookup command at the command prompts, type server 8.8.8.8 and enter

- Then continue as above with the command set type=SRV (no spaces before/after the = sign) and following instructions

Note you can replace 8.8.8.8 with any other public DNS server.  I chose Google's.

Example:

> server 8.8.8.8
Default Server:  google-public-dns-a.google.com
Address:  8.8.8.8

> set type=SRV
> _sip._tcp.cisco.com
Server:  google-public-dns-a.google.com
Address:  8.8.8.8

Non-authoritative answer:
_sip._tcp.cisco.com     SRV service location:
          priority       = 1
          weight         = 0
          port           = 5060
          svr hostname   = vcsgw.cisco.com
>

[Sean Grubb]

I know that this is a bit of an old thread, but hopefully you can still help me. We have a setup with a primary and secondary cucm and a primary and secondary IM&P server. Before now we were installing clients and manually inputting the primary IM&P server address for it to connect on first run of the Jabber client, but after realizing how long that is taking to get to every employee we are looking into a mass deployment situation.

When creating these DNS SRV records, do they need to be created for each of these servers or just the primary CUCM server? Or should it point to the primary IM&P server? Or am I getting confused and the _cisco-uds goes on the CUCM server whereas the _cuplogin goes on the IM&P server?

Any help will be appreciated!

[rikardkrvaric]

Sean, 

You only need to create the SRV record for the CUCM server you want the Jabber Client to hit.

So, if you have 1 Publisher, and 8 subscribers, you can do SRV records for 9, or for 1.

_cisco-uds._tcp.example.com = CUCM servers

_cuplogin._tcp.example.com = IM&P servers

Although we have setup proper priorities and weights on the different SRV records (for _cisco-uds._tcp.example.com) TAC has told me Jabber client does not follow the priority and weights. Rather, it just hits ANY of the Servers it finds in the DNS SRV record.