[SR-Users] Topoh hiding prefixes

[Efelin Novak]

Hi folks,

I have a topology like this:

UA -> kamailio -> PSTN GW.

When I'm placing calls to a PSTN I have to append prefixes so the PSTN
GW knows how to route the call. So the request-uri is
<prefix><number>@<gateway_ip> e.g. 999123456 at 192.168.1.1. When the UA
calls to the GW a "200 OK" message contains a contact header with
999123456 at 192.168.1.1. This is a problem because I don't want my
customers to see gateway prefixes.

The Topoh module only hides IP addresses or the  domain part. Is there
any way to remove prefixes. This document
(http://www.kamailio.org/events/2011-Cluecon/DCM-kamailio-security.pdf)
stated "encoding IP and prefixes can be set via parameters". Can I
remove prefixes from the contact in any other way than some contact
header substitutions?

Thanks

Efelin