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DHCP Option 242 in TMS 13.2.2

    Would like to know what exactly does DHCP send to TMS in Option 242? Everything I have seen regarding this is in regard to VoIP phones.

What we are expierencing is that endpoints are not recieving their persistent settings when they are being factory reset, going from one classification to another.  Does option 242 point TMS to the proper DNS?              


DHCP Option 242 in TMS 13.2.2

What it does is to populate the external manager address.

At least the TMS docu says its an IP address. As you write dns you want to check on that.

It might also depend on what happens after you did a default reset. (like if the ip address of the endpoint changed).

In TMS you define how you keep track of the endpoint, in your case I would use Mac

Default System Identifier Type to Track Systems

> Mac/Hostname/IP

What do mean by "going from one classification to another"?

Which endpoints to you use with which software versions.

Any other DHCP options set?

Please remember to rate helpful responses and identify helpful or correct answers.

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Re: DHCP Option 242 in TMS 13.2.2


If you configure dhcp option 242 on your dhcp server, your endpoints will be able to get the TMS server address from dhcp along with the DNS servers and IP address for that network.

The issue you are experiencing is potentially a defect if you are using TC software based endpoints (c\ex series systems). I forget the defect number but I know it was resolved in TC 6.3.

The easiest way to figure out why this is not working for you is to take a span port capture from the codec that is not pulling its template when it switches networks. I assume when you are referring to switching networks you are talking about classified and non-classified. Take the capture when you switch networks and then filter the traffic for any DNS queries or queries towards the TMS IP address. If you are supplying the TMS host name using option 242 then the endpoint will need to do a DNS lookup first. Make sure this is happening, and verify the DNS server it is using for the query. If you are supplying the TMS IP address, check the capture for this address and analyze the communication between the endpoint and TMS.

Hope that helps!

Chad P.
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