[OpenSIPS-Users] Trouble SDP o-line

Muhammad Shahzad Shafi shahzad at voip-demos.com
Mon Jul 22 19:17:36 CEST 2013

According to RFC4566, C and O lines may have different IP addresses, it 
quite normal,

   "For privacy reasons, it is sometimes desirable to obfuscate the
    username and IP address of the session originator.  If this is a
    concern, an arbitrary <username> and private <unicast-address> MAY 
    chosen to populate the "o=" field, provided that these are selected
    in a manner that does not affect the global uniqueness of the 

Ref. http://tools.ietf.org/html/rfc4566#page-12

Anyways, you may use textops modules to change IP in O line same as C. 
Alternatively you may try nathelper module's fix_nated_sdp method.

Thank you.

On 2013-07-22 15:09, Julian Santer wrote:
> Hi,
> we are using OpenSips 1.6.4 (starting with the migration to 1.8.x)
> with nat_traversal module and Mediaproxy 2.5.2.
> The Media at the moment will be relayed over the Mediaproxy only if
> it is necessary.
> For the routing to PSTN we have two carriers.
> One of them ignores the o-line in SDP the other not.
> So we got problems with one of the carrier, when in the o-line is a
> private or invalid IP and also if the o-line is not the same as the
> c-line
> Example:
> OK:
> v=0
> o=root 2142162444 2142162444 IN IP4 $PUBLIC_IP
> s=call
> KO:
> v=0
> o=user 15997790 15997790 IN IP4 $PRIVATE_IP
> s=call
> But also if we relay over our Mediaproxy, only the c-line will be 
> changed.
> KO:
> v=0
> o=- 46755 32066 IN IP4 $INVALID_IP
> s=bjoraow
> Have I any possiblity to inject the o-line or shouldn't I do that?
> Will the change of the o-line break the signalization?
> Should the carrier ignore the IP in the o-line?
> Thank you for any help.
> Best Regards,
> Julian
> _______________________________________________
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> Users at lists.opensips.org
> http://lists.opensips.org/cgi-bin/mailman/listinfo/users

Mit freundlichen Grüßen
Muhammad Shahzad
CISCO Rich Media Communication Specialist (CRMCS)
CISCO Certified Network Associate (CCNA)
Cell: +49 176 99 83 10 85
MSN: shari_786pk at hotmail.com
Email: shaheryarkh at googlemail.com

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