[asterisk-users] PJSIP ports, multiple IP addresses and wrong owner

Recursive lists at binarus.de
Sun Dec 21 04:54:33 CST 2014

Dear list,

I am currently trying to send faxes via T.38 using PJSIP (newest version 2.3) with Asterisk 13.0.2. After having configured PJSIP, I have seen several things the cause of which I would like to know.

1) Ports and IP addresses which PJSIP bind to

I have configured one transport like that:

type = transport
protocol = udp
bind =

Nevertheless, PJSIP binds to more ports and IP addresses than expected:

root at spock:~# netstat -apnv | grep asterisk
udp   0   0*  21416/asterisk  
udp   0   0*  21416/asterisk  
udp   0   0*  21416/asterisk  

This is on a box which has one physical NIC which has configured multiple IP addresses by ethernet aliasing:

eth0      Link encap:Ethernet  HWaddr 02:01:01:01:05:01  
          inet addr:  Bcast:  Mask:
          RX packets:32321283 errors:0 dropped:0 overruns:0 frame:0
          TX packets:171282095 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:9690993944 (9.0 GiB)  TX bytes:244294378305 (227.5 GiB)

eth0:1    Link encap:Ethernet  HWaddr 02:01:01:01:05:01  
          inet addr:  Bcast:  Mask:
[and so on, 10 IP addresses]

So what is the meaning of the additional ports PJSIP is opening, and why does it open these on all IP addresses?

By the way, I already have tried to make sure that it's really PJSIP which opens these. After all, I can tell for sure that they are NOT opened if I use chan_sip instead of PJSIP with an otherwise identical software version (I am compiling myself so I was able to produce two flavors of Asterisk which are identical except that one uses chan_sip, the other one chan_pjsip). I furthermore have compiled an additional Asterisk / PJSIP flavor with as few modules, channels etc. as possible, but this flavor still opens the additional ports.

2) Wrong owner in SDP (o= line)

I think this problem relates to the first one.

I am currently unable to send a fax, and I suspect this is due to the fact that Asterisk / PJSIP produces a wrong owner record. A typical INVITE:

No.     Time        Source                Destination           Protocol Length Info
   9225 7.503015         xx.xxx.xx.xxx         SIP/SDP  886    Request: INVITE sip:004982349663847 at fpbx.de | 

Frame 9225: 886 bytes on wire (7088 bits), 886 bytes captured (7088 bits)
Ethernet II, Src: MS-NLB-PhysServer-01_01:01:05:01 (02:01:01:01:05:01), Dst: D-Link_03:a4:18 (00:1b:11:03:a4:18)
Internet Protocol Version 4, Src: (, Dst: xx.xxx.xx.xxx (xx.xxx.xx.xxx)
User Datagram Protocol, Src Port: 5060 (5060), Dst Port: 5060 (5060)
Session Initiation Protocol (INVITE)
    Request-Line: INVITE sip:00498234xxxxxxx at itsp.de SIP/2.0
        Method: INVITE
        Request-URI: sip:00498234xxxxxxx at itsp.de
            Request-URI User Part: 0049823xxxxxxx
            Request-URI Host Part: itsp.de
        [Resent Packet: False]
    Message Header
        Via: SIP/2.0/UDP;rport;branch=z9hG4bKPj7afca7e1-0c3b-494f-978a-844fa19cfc4a
            Transport: UDP
            Sent-by Address: yy.yyy.yy.yyy
            Sent-by port: 5060
            RPort: rport
            Branch: z9hG4bKPj7afca7e1-0c3b-494f-978a-844fa19cfc4a
        From: <sip:77748zb1ye at fpbx.de>;tag=4e855dd1-4a8c-41a9-9524-038d32c08ce3
            SIP from address: sip:username at itsp.de
                SIP from address User Part: username
                SIP from address Host Part: itsp.de
            SIP from tag: 4e855dd1-4a8c-41a9-9524-038d32c08ce3
        To: <sip:004982349663847 at fpbx.de>
            SIP to address: sip:00498234xxxxxxx at itsp.de
                SIP to address User Part: 00498234xxxxxxx
                SIP to address Host Part: itsp.de
        Contact: <sip:username at yy.yyy.yy.yyy>
            Contact URI: sip:username at yy.yyy.yy.yyy
                Contact URI User Part: username
                Contact URI Host Part: yy.yyy.yy.yyy
        Call-ID: ad46d131-91ab-44bd-8b7e-40551b7fd8e5
        CSeq: 20417 INVITE
            Sequence Number: 20417
            Method: INVITE
        Supported: 100rel, timer, replaces, norefersub
        Session-Expires: 1800
        Min-SE: 90
        Content-Type: application/sdp
        Content-Length:   238
    Message Body
        Session Description Protocol
            Session Description Protocol Version (v): 0
            Owner/Creator, Session Id (o): - 928891384 928891384 IN IP4
                Owner Username: -
                Session ID: 928891384
                Session Version: 928891384
                Owner Network Type: IN
                Owner Address Type: IP4
                Owner Address:
            Session Name (s): Asterisk
            Connection Information (c): IN IP4 yy.yyy.yy.yyy
                Connection Network Type: IN
                Connection Address Type: IP4
                Connection Address: yy.yyy.yy.yyy
            Time Description, active time (t): 0 0
                Session Start Time: 0
                Session Stop Time: 0
            Media Description, name and address (m): audio 11544 RTP/AVP 0 101
                Media Type: audio
                Media Port: 11544
                Media Protocol: RTP/AVP
                Media Format: ITU-T G.711 PCMU
                Media Format: DynamicRTP-Type-101
            Media Attribute (a): rtpmap:0 PCMU/8000
                Media Attribute Fieldname: rtpmap
                Media Format: 0
                MIME Type: PCMU
                Sample Rate: 8000
            Media Attribute (a): rtpmap:101 telephone-event/8000
                Media Attribute Fieldname: rtpmap
                Media Format: 101
                MIME Type: telephone-event
                Sample Rate: 8000
            Media Attribute (a): fmtp:101 0-16
                Media Attribute Fieldname: fmtp
                Media Format: 101 [telephone-event]
                Media format specific parameters: 0-16
            Media Attribute (a): ptime:20
                Media Attribute Fieldname: ptime
                Media Attribute Value: 20
            Media Attribute (a): maxptime:150
                Media Attribute Fieldname: maxptime
                Media Attribute Value: 150
            Media Attribute (a): sendrecv

Note that in the SDP part it claims the Owner/Creator (o=) to be which is the main IP address of the box (eth0), but not the one where Asterisk / PJSIP should bind to.

So, I've got two questions here: First, how do I tell Asterisk / PJSIP which IP address it should use as the owner (o=) IP address (I didn't see anything in the docs which would allow for that), and secondly, could a wrong owner be the reason for the ITSP to hang up immediately after the T.38 re-invite? In other words, does a wrong owner harm at all?

Thank you very much for any ideas,


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