[Serusers] DNS Resolution of SDP-"Connection Address" at SER

[Nils Ohlmeier]

Just a short note and/or question: how are FQDN in SDP suppose to work if the 
FQDN is only resolveable in the local network (especially behind NAT)?
And how should or can a UA determine if its FQDN is only locally resolveable 
or not?
IMHO FQDN in SDP only introduces additional trouble with NATs.

Regards
  Nils

On Monday 13 June 2005 15:03, Gerhard Zweimüller wrote:
> Thanks for your answer.
>
> The funny thing is: I am trying quite hard to convince the vendor (actually
> a well-known VoIP-chip/module/appliance maker) that FQDN in SDP is a good
> (and allowed) thing.
>
> Even more funny: In the preceding firmware-release FQDN was no problem. But
> in the current release they apparently *removed* the FQDN-support and now
> they try to convince me that FQDN in SDP is not allowed :-(  Although I
> sent them RFCs and everything to prove them wrong.
>
> But there you go.
>
> I tried your suggestion with fix_nated_sdp and so far it seems to work.
> Thanks for the tip!
>
> Hopefully the vendor will change its RFC-support policy soon.
>
> Kind regards,
> Gerhard
>
>
> -----Original Message-----
> From: Zeus Ng [mailto:zeus.ng at isquare.com.au]
> Sent: Sunday, June 12, 2005 8:30 AM
> To: Gerhard Zweimüller
> Cc: serusers at lists.iptel.org
> Subject: RE: [Serusers] DNS Resolution of SDP-"Connection Address" at SER
>
> Forcing SER to do stuff in order to fix problem UA implementation, I don't
> think this is a good approach. Using FQDN as connection information in SDP
> is the recommended approach in RFC 2327, though few UA do this. I would
> suggest you contact the vendor to fix the UA that can't work with DNS.
>
> Have a look on the fix_nated_sdp() function in nathelper. I haven't tried
> this before but it might work. However, there is no guarantee. Let us know
> if it works.
>
> > -----Original Message-----
> > From: Gerhard Zweimüller
> > Sent: Saturday, 11 June 2005 11:07 PM
> > To: serusers at lists.iptel.org
> > Subject: [Serusers] DNS Resolution of SDP-"Connection Address" at SER
> >
> >
> >  Hi Serusers,
> >
> > I have a problem with DNS resolution in SIP/SDP "Connection
> > Information"
> > / "ConnectionAddress". Maybe somebody can help me:
> >
> > In the network we use SIP-UAs that are integrated into ADSL-Modems
> > from Allied Telesyn (AT RG 634).
> > The SIP-client itself works OK. But when the unit is given a
> > system-name in the configuration, it will always use its DNS-name
> > instead of its IP-addr as "Connection Address" in the "Connection
> > Information" in SDP in INVITE and corresponding OK messages.
> >
> > Now we want to add SIP-UAs that are NOT capable of resolving DNS-Names
> > in the "Connection Address" field.
> > Alle messages pass through SER of course and the SDP-part so far
> > remains unchanged.
> >
> > Now my question to the list:
> > Is there a simple way of forcing SER to do the DNS-resolution of in
> > incoming message, put in the IP-address in "Connection Address" and
> > forward it to the other UA?
> >
> > Thanks a lot in advance!
> > Gerhard
> >
> >
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> > serusers at lists.iptel.org http://lists.iptel.org/mailman/listinfo/serusers
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