13 Jun
2005
13 Jun
'05
3:03 p.m.
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@isquare.com.au]
Sent: Sunday, June 12, 2005 8:30 AM
To: Gerhard Zweimüller
Cc: serusers(a)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(a)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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15 Jun
15 Jun
11:44 p.m.
New subject: [Serusers] DNS Resolution of SDP-"Connection Address" at SER
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@isquare.com.au]
Sent: Sunday, June 12, 2005 8:30 AM
To: Gerhard Zweimüller
Cc: serusers(a)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(a)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
_______________________________________________
Serusers mailing list
serusers(a)lists.iptel.org http://lists.iptel.org/mailman/listinfo/serusers
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16 Jun
16 Jun
2 a.m.
New subject: [Serusers] DNS Resolution of SDP-"Connection Address" at SER
In principle, your point is totally valid. That's the inherit problem of
combining UDP and NAT.
OTOH, human intelligence is important in proper implementation.
Looking closer to the problem, if the UA is capable of detecting what kind
of NAT router it is behind, it SHOULD put the correct connection info for
BOTH SIP and SDP packet, either public IP or FQDN of the NAT router, not
private IP nor FQDN of the device itself.
If the UA is not capable of detecting NAT, the method we just tried could
help. However, those products shall been dump into the bin, as least I will
do so.
If UA is not behind NAT but having FQDN only resolvable internally, it's the
network administrator's fault. That device should not be put on the public
internet. Will you setup a web server for the general public that no one
else can resolve the IP?
Zeus
-----Original Message-----
From: Nils Ohlmeier
Sent: Thursday, 16 June 2005 7:45 AM
To: serusers(a)lists.iptel.org
Cc: Gerhard Zweimüller; Zeus Ng
Subject: Re: [Serusers] DNS Resolution of SDP-"Connection
Address" at SER
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@isquare.com.au]
Sent: Sunday, June 12, 2005 8:30 AM
To: Gerhard Zweimüller
Cc: serusers(a)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(a)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
_______________________________________________
Serusers mailing list
serusers(a)lists.iptel.org http://lists.iptel.org/mailman/listinfo/serusers
_____________________________________________________________ _______ Dieses Mail wurde vom Infotech SecureMail
Service
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zu
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been classified as secure. For more information
on Infotech
SecureMail
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7052
days inactive
7055
days old
2 comments
3 participants
participants (3)
-
Gerhard Zweimüller -
Nils Ohlmeier -
Zeus Ng