MRA DNS setup for TFTP and HTTP download of firmware and configs

[tato386]

How do MRA connected phones get the hostname or IP of their TFTP server?  Do they just default to, or assume, it is the same as the "collab-edge" DNS records?

TIA,

Diego

[Jaime Valencia]

Suggest you review MRA troubleshooting sessions from the Cisco Live catalog where endpoint registration over MRA is covered. 

[tato386]

Thank you Jaime will do

[Rajan]

Hi Diego,

While connecting via MRA, the phones will only get the external DNS SRV record which will point to the Expressway E server/servers and wont directly get the TFTP details. Its the expressway which knows the TFTP server details and will resolve it. Expressway forwards the requests from phones to the configured TFTP servers.

HTH
Rajan
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[tato386]

That makes sense that it should work that way but the phone itself (via display or web) does not show any TFTP server configured even after connecting and successfully registering with the Exp-E.  So I guess it's working but I would feel better if I can see confirmation from the phone. 

[Rajan · Accepted solution]

Hi Diego,

I don't think the phone will get the CUCM TFTP IP during MRA as its the Expressway servers which proxies the TFTP requests from phones and hence the phones/endpoints will never know about the CUCM TFTP details as such. Only thing it will get is the CUCM IP to register again via Expressway.

The below link provides more insight on how MRA works and how to test in detail. Probably this will clarify.

https://netcraftsmen.com/cisco-mobile-remote-access-troubleshooting-basic-connectivity/ 

HTH
Rajan
Please rate all useful posts by clicking the star below and mark solutions as accepted wherever applicable

[tato386]

Excellent article Rajan, highly detailed and very informative.  In my case I had to add ".sgn" to the end of the filename when retrieving configs.  I guess the article was written before signed configs were default or more commonly used?  As a bonus, as I was perusing the downloaded configs, I found that I had an outdated IP for one of my NTP servers.  Maybe I should start using FQDN for that, LOL.

Thank you very much!

Diego

[Rajan]

Hi Diego,

Glad it helped.

Thanks,

Rajan