[Serusers] SER losing SIP registrations

Thu Jun 23 13:44:26 CEST 2005

OK, the REGISTER message contains a private IP in the contact. That
would force SER to rewrite the IP address with the public IP of the NAT
and the user agent is probably unable to match the contact and find out
what the expires value set by the server is. That explains why it works
with Expires: 60 header field parameter but does not work with
;expires=60 contact parameter.

There are two options:

1) Hack -- insert Expires: 50 header field into the reply using
   append_to_reply function from textopts module. Note that the value you
   insert this way must be lower than the value of expires parameter in the
   contact.

2) Use fix_nated_register instead of fix_nated_contact for REGISTER
   messages. This function does not rewrite the IP in contact, instead
   it would append the public IP and port used by the NAT as a parameter
   of Contact header field. The two values will be stored separately in
   the user location database. When forwarding a message to the contact,
   the Request-URI will contain the private IP of the user agent, but
   the message will be sent to the public IP of the NAT (destination set
   will be used). This way the Contact in 200 OK reply will be not
   modified and the user agent should be able to set the expires value
   properly.

   Jan.

On 23-06-2005 17:59, Chia Huey Lim wrote:
> Sure...
> 
> SER:
> REGISTER sip:xxx.xxx.xxx.xxx SIP/2.0
> Via: SIP/2.0/UDP 192.168.0.4:5060;branch=z9hG4bKd9e688a70
> Max-Forwards: 70
> Content-Length: 0
> To: 5008 <sip:18182002 at xxx.xxx.xxx.xxx>
> From: 5008 <sip:18182002 at xxx.xxx.xxx.xxx>;tag=1f55b6cd5586c2d
> Call-ID: 928d75b5b6c7d128a0ccaf24e5b52c74 at 192.168.0.4
> CSeq: 1028949335 REGISTER
> Contact: 5008 <sip:18182002 at 192.168.0.4:5060;user=phone>;expires=60
> Allow: NOTIFY
> Allow: REFER
> Allow: OPTIONS
> Allow: INVITE
> Allow: ACK
> Allow: CANCEL
> Allow: BYE
> User-Agent: InterEdge-ieta200
> 
> ASTERISK:
> REGISTER sip:xxx.xxx.xxx.xxx SIP/2.0
> Via: SIP/2.0/UDP 192.168.0.4;branch=z9hG4bKf91124aeb
> Max-Forwards: 70
> Content-Length: 0
> To: 603200661 <sip:603200661 at xxx.xxx.xxx.xxx>
> From: 603200661 <sip:603200661 at xxx.xxx.xxx.xxx>;tag=7f4a78971dd573b
> Call-ID: 59a4ee90d5fbe74f8de459fb2506acf0 at 192.168.0.4
> CSeq: 937060361 REGISTER
> Contact: 603200661 <sip:603200661 at 192.168.0.4;user=phone>;expires=1200
> Allow: NOTIFY
> Allow: REFER
> Allow: OPTIONS
> Allow: INVITE
> Allow: ACK
> Allow: CANCEL
> Allow: BYE
> Authorization:Digest
> response="869ebcdfd4f83cfd805c0b03e768b9a5",username="603200661",realm="xxx"
> ,nonce="297966ac",uri="sip:xxx.xxx.xxx.xxx"
> User-Agent: InterEdge-ieta200
> 
> Regards,
> Chia
> 
> 
> -----Original Message-----
> From: 'Jan Janak' [mailto:jan at iptel.org] 
> Sent: Thursday, June 23, 2005 5:44 PM
> To: Chia Huey Lim
> Cc: 'Juan Carlos Castro y Castro'; serusers at lists.iptel.org
> Subject: Re: [Serusers] SER losing SIP registrations
> 
> Could send me also the REGISTER messages ?
> 
>   Jan.
> 
> On 23-06-2005 17:36, Chia Huey Lim wrote:
> > I am facing the same problem too, one of the UA that I am testing on does
> > not re-register itself. It has no problem re-registering itself to
> asterisk.
> > 
> > I compared the ethereal trace for the registration on SER and Asterisk.
> And
> > I found that Asterisk append "Expires: xxx" above the "Contact: " while
> SER
> > does not. Anything that I can do to append "Expires: xxx" in the 200 ok
> > packet that SER is sending out?
> > 
> > Below is the comparison:
> > 
> > SER:
> > Ä¸e`SIP/2.0 200 OK
> > Via: SIP/2.0/UDP
> >
> 192.168.0.4:5060;branch=z9hG4bKef17e9623;rport=32914;received=xxx.xxx.xxx.xx
> > x
> > To: 5008
> > <sip:18182002 at xxx.xxx.xxx.xxx>;tag=856642a4d7f9f16db9502202a011388b.db9a
> > From: 5008 <sip:18182002 at xxx.xxx.xxx.xxx>;tag=1f55b6cd5586c2d
> > Call-ID: 928d75b5b6c7d128a0ccaf24e5b52c74 at 192.168.0.4
> > CSeq: 1028949336 REGISTER
> >
> Contact:<sip:18182002 at xxx.xxx.xxx.xxx:32914;user=phone>;expires=60;received=
> > "sip:xxx.xxx.xxx.xxx:32914"
> > Server: Sip EXpress router (0.9.0 (i386/linux))
> > Content-Length: 0 
> > 
> > ASTERISK:
> > ÄÄ
> > x9SIP/2.0 200 OK
> > Via: SIP/2.0/UDP
> > 192.168.0.4;branch=z9hG4bKf91124aeb;received=xxx.xxx.xxx.xxx;rport=32914
> > From: 603200661 <sip:603200661 at xxx.xxx.xxx.xxx>;tag=7f4a78971dd573b
> > To: 603200661 <sip:603200661 at xxx.xxx.xxxx.xxx>;tag=as4f0c60fe
> > Call-ID: 59a4ee90d5fbe74f8de459fb2506acf0 at xxx.xxx.xxx.xxx
> > CSeq: 937060361 REGISTER
> > User-Agent: xxx
> > Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER
> > Expires: 1200
> > Contact: <sip:603200661 at xxx.xxx.xxx.xxx;user=phone>;expires=1200
> > Date: Wed, 22 Jun 2005 04:36:20 GMT
> > Content-Length: 0
> > 
> > Thanks.
> > 
> > Regards,
> > Chia
> > 
> > 
> > -----Original Message-----
> > From: serusers-bounces at iptel.org [mailto:serusers-bounces at lists.iptel.org] On
> > Behalf Of Jan Janak
> > Sent: Thursday, June 23, 2005 4:39 PM
> > To: Juan Carlos Castro y Castro
> > Cc: serusers at lists.iptel.org
> > Subject: Re: [Serusers] SER losing SIP registrations
> > 
> > On 22-06-2005 17:57, Juan Carlos Castro y Castro wrote:
> > > Our company has a call center implementation on a client with up to 100
> > > support personnel using X-Lite version 1050 softphones running under
> > > Windows 98. Until a few days ago, the softphones were logged in directly
> > > on our PBXs. Now, they log onto a separate SER 0.8.14 box and the PBXs
> > > forward calls to SER. That was needed to unify queue management.
> > > 
> > > It works. But some softphones are being randomly kicked out of SER, it
> > > seems SER isn't receiving the refresh REGISTER messages from the
> > > softphones. The re-register timeout is set to 500 seconds on the
> > > softphones. There's a lot of "removing spare zombie" and "Binding
> > > '<user>','<url>' has expired" messages in /var/log/messages.
> > 
> >   The message means that SER did not receive REGISTER re-fresh and is
> >   thus removing the contact from the user location database.
> > 
> >   Pick one user agent that has this problem and install ngrep monitor on
> >   the server to monitor all REGISTER messages from that user agent. This
> >   way you could find out if the problem is in the user agent or network
> >   (in this case you will not see REGISTER refresh messages on the
> >   server) or in SER (in that case you will see them but SER probably
> >   fails to process them).
> > 
> >   Also make sure that SER is not configured to shorten the registration
> >   period. When registrar receives a REGISTER message, it is free to use
> >   shorter expires value for the Contac than what was suggested by the
> >   user agent in the request. In this case the real expires value of the
> >   contact will be in 200 OK and user agents are suppose to pick it up
> >   from there and update the refresh interval accordingly. This may not
> >   work in the case when Contact IP address is rewritten by the server
> >   for the purpose of NAT traversal. In this case the user agent will be
> >   unable to find its contact (because it has been rewritten) and will
> >   not update the refresh interval (resulting in expired registrations).
> > 
> > > For now, we're instructing the client to increase the timeout to 10
> > > hours on the softphones in which the problem happens most often. I don't
> > > know if that's really the right thing to do, I think we should somehow
> > > make sure the re-registers are done in a timely fashion and retried, but
> > > I could not find ant SER configuration option related to that. What
> > > should I do?
> > 
> >   You can configure the maximum allowed expires value in SER, if a user
> >   agent tries to REGISTER a contact with longer expires value than it
> >   will be automatically updated by registrar to the value of max_expires
> >   parameter.
> > 
> >   There is also min_expires parameter in registrar module but that one
> >   should not be used because the current implementation violates
> >   RFC3261.
> > 
> >   If you are using any of the two parameter than it might be a good idea
> >   to retry without them (to see if the problem persists).
> > 
> >     Jan.
> > 
> 