Expressway Edge - custom DNS or Custom Route

[jleavy]

Greetings from Dublin,

We have a Cisco Expressway Edge sitting in our DMZ. We use it for making SIP calls to a number of external agencies.

One agency have an issue on their side - they have an incorrect DNS record setup and they can't change it quickly. For my part, I know that the IP address of their Expressway edge should be.

Is it possible for me to either:

1. Call them via their IP address some way? like xoxxox@EXTERNAL.IP.ADDR ? (I tried but call fails instantly)

2. Create a custom route between my edge and their edge so that DNS isn't needed?

3. Create a custom DNS entry in some way on the ExpressWay-E?

It would be my preference to be able to call their IP address and not mess with DNS or static routes, but I'm not sure how to achieve this. The edge keeps adding @my.domain at the end of the IP address when I review the logs.

Thanks,

Joe

[Marcelo Morais]

Hi @jleavy,

 could you please send the following info:

1) Status > Search History > search detail of the call

2) Configuration > Dial Plan > Transforms

3) Configuration > Dial Plan > Search Rules

Best regards,

 Marcelo Morais

[jleavy]

Hi @Marcelo Morais,

Good morning and thanks for the response.

1) Status > Search History > search detail of the call

==> See TXT attached for calling their DNS....

When I call the 56253@[THIER IP] it does not appear in the search at all?

2) Configuration > Dial Plan > Transforms

See pic attached. I only removed a mention of our DNS name.

3) Configuration > Dial Plan > Search Rules

OH - I wonder is this the problem - IP = STOP in search rules?

Again I only removed our DNS name from the file,

Thanks a million,

Joe

[Nick Halbert-Lillyman]

If your endpoints are registered to CUCM, they won't support dialling @ip, hence why you need to dial @domain from the endpoint and transform it on the Expressway.

[Nick Halbert-Lillyman · Accepted solution]

Create a transform rule (Configuration > Dial Plan > Transform) that translates their domain to an IP address, e.g.

Type: Suffix

Behaviour: Replace

String: @their.domain.com

Replace String: @1.1.1.1

[jleavy]

Hi @Nick Halbert-Lillyman,

I'm accepting this as the solution as it appears to have gotten me a little further into their network. I can now see that the search is indeed transforming into the IP address correctly and I'm getting a new error (which I recon is again their issue).

I'll escalate to them as I'm happy I can call other destinations.

Bandwidth node	Default zone
Target alias 1	56253@IP.Add.re.ss (H323Id)
Protocol	H323 <==Looks wrong
Address	P.Add.re.ss:1720
Encryption type	None
Reason	Unreachable destination
Cause	No route to destination

[Nick Halbert-Lillyman]

Did you put the transform on Expressway C or E? It needs to be on Exp-E and you need a search rule for "any IP address" targeting your DNS zone, and to have "calls yo unknown IP" addresses set to "call direct"

[jleavy]

 Hi @Nick Halbert-Lillyman,

Your correct. I put the transform into the ExpressWay-C and not the Edge.

I've now removed it from the 'C' and added it to the 'E' however I'm not sure about the search rule you mentioned, would you mind explaining that a little more or...? (sorry, early Friday morning)!

Attached is from the ExpressWay Edge.

Sleepy Joe

[Nick Halbert-Lillyman]

You probably already have a search rule for "any alias" - copy that one but change to "any ip address". Then there's an option for calls to unknown IP addresses (I think it's in dial plan, on my phone so can't check) set it to "call direct".

[jleavy]

Hi @Nick Halbert-Lillyman,

Thanks for the additional information.

No progress really, however I did find that rule for unknown addresses and call direct. The protocol was incorrect, so i changed it to any.

I now get the attached in the logs. Again, this could be their issue!!

1. It's transforming correctly, right?

2. It appears to the 'dialing' out..... right?

That's really all i can check?

See TXT attached.

Joe

[Nick Halbert-Lillyman]

Given that the search shows "Local zone match" at the end, I suspect that you need to set your search rule for "Any IP address" and "any alias" needs to be higher priority than the "Local zone" search rule, as it shouldn't be searching the local zone (which is endpoints registered to that Expressway).

Maybe take a screen shot of the list of your search rules?

[jleavy]

Hi @Nick Halbert-Lillyman,

Thanks again really for bearing with me on this.

See a screen dump of my search rules from the ExpressWay Edge. It appears to be already set to a higher priority?

Joe

[Nick Halbert-Lillyman]

You've got both the "any alias" and "any IP address" search rules - you need to change the "target" of both to be your DNS zone.

It's basically telling Expressway-Edge to look it up if it's not one of your endpoints.

[Marcelo Morais]

Hi @jleavy@
 glad to hear that you are almost solving all your questions.

I would like to add some rules of thumb that could help you:

1) The most specific Pattern String must have a lower Priority;
2) Whenever possible, try to identify your Source, avoid Any;
3) Use the On Match = Stop, if there is only one path (Target) to that route (Pattern String).

Note: if you are able to create specifics Pattern String using the On Match = Stop, then your future troubleshooting will be easier.

Best regards,
 Marcelo Morais