Kamailio not updating CSeq after uac_auth() for ACK - sr-users

17 Dec 2020

Hi, Here is setup details
Kamailio Proxy a <-----> Kamailio Proxy b  <-----> Asterisk
Kamailio proxy b auth based on IP Kamailio Proxy a
1. Kamailio proxy sends an Invite request to Kamailio proxy b with CSeq:
102 INVITE
2. Kamailio proxy b check again IP auth and sends invite request to
asterisk with CSeq: 102 INVITE
4 asterisk response with 401 Unauthorized with  CSeq: 102
5. Kamailio proxy b sends ACK request with CSeq: 102 ACK
6. Kamailio proxy b sends INVITE request with CSeq: 103 INVITE
7. Asterisk sends 100 trying and 180 ringing with CSeq: 103 INVITE
8. Kamailio proxy b relay 180 ringing with  CSeq: 102 INVITE
9. Asterisk send 200 Ok with CSeq: 103 INVITE and proxy b relay it to proxy
a with CSeq: 102 INVITE
10. Now Proxy a send an ACK with CSeq: 102 ACK and proxy b relay ACK to
asterisk with CSeq: 102 ACK

Now asterisk is retransmitting 200 ok with CSeq: 103 INVITE and proxy a is
sending ACK with Cseq: 102 ACK

Same happing in case of 487 Request Terminated

Here is my config

modparam("dialog", "default_timeout", 10800) # 3h
modparam("dialog", "dlg_match_mode", 1)
modparam("dialog", "db_mode", 0)
modparam("dialog", "send_bye", 1)
modparam("dialog", "track_cseq_updates", 1)
modparam("uac","auth_username_avp","$avp(auser)")
modparam("uac","auth_password_avp","$avp(apass)")
modparam("uac","auth_realm_avp","$avp(arealm)")

modparam("tm", "failure_reply_mode", 3)
# default retransmission timeout: 3 sec
modparam("tm", "fr_timer", 2000)
modparam("tm", "retr_timer1", 250)
modparam("tm", "retr_timer2", 500)
# default invite retransmission timeout after 1xx: 60 sec
modparam("tm", "fr_inv_timer", 60000)
modparam("tm", "reparse_on_dns_failover", 0)

if (is_method("INVITE") && !has_totag()) {
        dlg_setflag(FLD_RTPPROXY);
        dlg_manage();
    }
    route(RELAY);

route[RELAY] {

    # At this point all checks are passed
    t_on_branch("MANAGE_BRANCH");
    t_on_reply("MANAGE_REPLY");
    t_on_failure("MANAGE_FAILURE");
    if(is_method("INVITE") && isflagset(FLT_FROMDID)) {
     #$fd = "sip.comms.kuflink.com";
      t_on_failure("RELAY_AUTH");
    }

    if (!t_relay()) {
        send_reply("500", "Cannot relay to $du/$ru");
    }
    exit;
}

failure_route[RELAY_AUTH] {
    t_on_branch("MANAGE_BRANCH");
    t_on_reply("MANAGE_REPLY");
    if (t_is_canceled()) {
        exit;
    }
    if(t_check_status("401|407")) {
        #$fd = "sip.comms.kuflink.com";
        $avp(auser) = "DID_UA_USERNAME";
        $avp(apass) = "DID_UA_PASSWORD";
        if (uac_auth()) {
            t_relay();
        }
        exit;
    }
}

route[WITHINDLG] {
    if (!has_totag()) {
        return;
    }

    if (is_method("BYE")) {
        rtpengine_delete();
    }

    # sequential request withing a dialog should
    # take the path determined by record-routing
    if (loose_route()) {
        route(DLGURI);
        if (is_method("ACK")) {
            # ACK is forwarded statelessly
            route(NATMANAGE);
        } else if (is_method("NOTIFY")) {
            # Add Record-Route for in-dialog NOTIFY as per RFC 6665.
            record_route();
        }
        route(RELAY);
        exit;
    }

    if (is_method("SUBSCRIBE") && uri == myself) {
        # in-dialog subscribe requests
        route(PRESENCE);
        exit;
    }
    if (is_method("ACK") ) {
        if (t_check_trans()) {
            # no loose-route, but stateful ACK;
            # must be an ACK after a 487
            # or e.g. 404 from upstream server
            route(RELAY);
            exit;
        } else {
            # ACK without matching transaction ... ignore and discard
            exit;
        }
    }
    send_reply("404","Not here");
    exit;
}

kamailio -v
version: kamailio 5.3.7 (x86_64/linux)
flags: USE_TCP, USE_TLS, USE_SCTP, TLS_HOOKS, USE_RAW_SOCKS, DISABLE_NAGLE,
USE_MCAST, DNS_IP_HACK, SHM_MMAP, PKG_MALLOC, Q_MALLOC, F_MALLOC,
TLSF_MALLOC, DBG_SR_MEMORY, USE_FUTEX, FAST_LOCK-ADAPTIVE_WAIT,
USE_DNS_CACHE, USE_DNS_FAILOVER, USE_NAPTR, USE_DST_BLACKLIST,
HAVE_RESOLV_RES, TLS_PTHREAD_MUTEX_SHARED
ADAPTIVE_WAIT_LOOPS 1024, MAX_RECV_BUFFER_SIZE 262144, MAX_URI_SIZE 1024,
BUF_SIZE 65535, DEFAULT PKG_SIZE 8MB
poll method support: poll, epoll_lt, epoll_et, sigio_rt, select.
id: unknown
compiled with gcc 6.3.0

uname -a
Linux example.com 4.15.0-124-generic #127-Ubuntu SMP Fri Nov 6 10:54:43 UTC
2020 x86_64 GNU/Linux

SIP logs
2020/12/17 10:08:18.483907 proxy-a.com:5060 -> 10.0.14.118:5060
INVITE sip:123456@proxy-a.com SIP/2.0
Record-Route: <sip:proxy-a.com;lr>
Via: SIP/2.0/UDP proxy-a.com:5060
;branch=z9hG4bKbe6d.10c4c5f001c66b8976214d4aef9f635c.1
Via: SIP/2.0/UDP did.com:5060;received=did.com
;branch=z9hG4bK45f94ed9;rport=5060
Max-Forwards: 70
From: "7654321" <sip:7654321@did.com>;tag=as55c522e1
To: <sip:123456@proxy-a.com>
Contact: <sip:7654321@did.com:5060>
Call-ID: 67675c7e636d6e773860255316e54779(a)did.com
User-Agent: ProxyA
CSeq: 102 INVITE
User-Agent: proxy
Date: Thu, 17 Dec 2020 10:08:18 GMT
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO,
PUBLISH, MESSAGE
Supported: replaces, timer
Remote-Party-ID: "7654321" <sip:7654321@did.com
...
 ;party=calling;privacy=off;screen=no
Content-Type: application/sdp
Content-Length: 885

2020/12/17 10:08:18.485063 10.0.14.118:5060 -> proxy-a.com:5060
SIP/2.0 100 trying -- your call is important to us
Via: SIP/2.0/UDP proxy-a.com:5060
;branch=z9hG4bKbe6d.10c4c5f001c66b8976214d4aef9f635c.1;rport=5060
Via: SIP/2.0/UDP did.com:5060;received=did.com
;branch=z9hG4bK45f94ed9;rport=5060
From: "7654321" <sip:7654321@did.com>;tag=as55c522e1
To: <sip:123456@proxy-a.com>
Call-ID: 67675c7e636d6e773860255316e54779(a)did.com
CSeq: 102 INVITE
Server: kamailio (5.3.7 (x86_64/linux))
Content-Length: 0

2020/12/17 10:08:18.485576 10.0.14.118:5060 -> 10.0.14.118:6000
INVITE sip:123456@proxy-a.com SIP/2.0
Record-Route: <sip:proxy-b.com;lr;did=d18.7a9>
Record-Route: <sip:proxy-a.com;lr>
Via: SIP/2.0/UDP proxy-b.com:5060
;branch=z9hG4bKbe6d.619fd995c3fc8764ce5cd9c7be7efeef.0
Via: SIP/2.0/UDP proxy-a.com:5060
;rport=5060;branch=z9hG4bKbe6d.10c4c5f001c66b8976214d4aef9f635c.1
Via: SIP/2.0/UDP did.com:5060;received=did.com
;branch=z9hG4bK45f94ed9;rport=5060
Max-Forwards: 70
From: "7654321" <sip:7654321@did.com>;tag=as55c522e1
To: <sip:123456@proxy-a.com>
Contact: <sip:7654321@did.com:5060>
Call-ID: 67675c7e636d6e773860255316e54779(a)did.com
User-Agent: ProxyA
CSeq: 102 INVITE
User-Agent: proxy
Date: Thu, 17 Dec 2020 10:08:18 GMT
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO,
PUBLISH, MESSAGE
Supported: replaces, timer
Remote-Party-ID: "7654321" <sip:7654321@did.com
...
 ;party=calling;privacy=off;screen=no
Content-Type: application/sdp
Content-Length: 885

2020/12/17 10:08:18.622867 10.0.14.118:6000 -> 10.0.14.118:5060
SIP/2.0 401 Unauthorized
Via: SIP/2.0/UDP proxy-b.com:5060
;branch=z9hG4bKbe6d.619fd995c3fc8764ce5cd9c7be7efeef.0;received=10.0.14.118;rport=5060
Via: SIP/2.0/UDP proxy-a.com:5060
;rport=5060;branch=z9hG4bKbe6d.10c4c5f001c66b8976214d4aef9f635c.1
Via: SIP/2.0/UDP did.com:5060;received=did.com
;branch=z9hG4bK45f94ed9;rport=5060
From: "7654321" <sip:7654321@did.com>;tag=as55c522e1
To: <sip:123456@proxy-a.com>;tag=as4107645c
Call-ID: 67675c7e636d6e773860255316e54779(a)did.com
CSeq: 102 INVITE
Server: proxy
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO,
PUBLISH, MESSAGE
Supported: replaces, timer
WWW-Authenticate: Digest algorithm=MD5, realm="sip1.comms.kuflink.com",
nonce="11139d33"
Content-Length: 0

2020/12/17 10:08:18.624034 10.0.14.118:5060 -> 10.0.14.118:6000
ACK sip:123456@proxy-a.com SIP/2.0
Via: SIP/2.0/UDP proxy-b.com:5060
;branch=z9hG4bKbe6d.619fd995c3fc8764ce5cd9c7be7efeef.0
Max-Forwards: 70
From: "7654321" <sip:7654321@did.com>;tag=as55c522e1
To: <sip:123456@proxy-a.com>;tag=as4107645c
Call-ID: 67675c7e636d6e773860255316e54779(a)did.com
CSeq: 102 ACK
Content-Length: 0

2020/12/17 10:08:18.625557 10.0.14.118:5060 -> 10.0.14.118:6000
INVITE sip:123456@proxy-a.com SIP/2.0
Record-Route: <sip:proxy-b.com;lr;did=d18.7a9>
Record-Route: <sip:proxy-a.com;lr>
Via: SIP/2.0/UDP proxy-b.com:5060
;branch=z9hG4bKbe6d.619fd995c3fc8764ce5cd9c7be7efeef.1.cs102
Via: SIP/2.0/UDP proxy-a.com:5060
;rport=5060;branch=z9hG4bKbe6d.10c4c5f001c66b8976214d4aef9f635c.1
Via: SIP/2.0/UDP did.com:5060;received=did.com
;branch=z9hG4bK45f94ed9;rport=5060
Max-Forwards: 70
From: "7654321" <sip:7654321@did.com>;tag=as55c522e1
To: <sip:123456@proxy-a.com>
Contact: <sip:7654321@did.com:5060>
Call-ID: 67675c7e636d6e773860255316e54779(a)did.com
User-Agent: ProxyA
CSeq: 103 INVITE
User-Agent: proxy
Date: Thu, 17 Dec 2020 10:08:18 GMT
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO,
PUBLISH, MESSAGE
Supported: replaces, timer
Remote-Party-ID: "7654321" <sip:7654321@did.com
...
 ;party=calling;privacy=off;screen=no
Content-Type: application/sdp
Content-Length: 885
Authorization: Digest username="xxxxx", realm="xxxx",
nonce="11139d33",
uri="sip:123456@proxy-a.com", response="qwewqeqwe", algorithm=MD5

2020/12/17 10:08:18.779483 10.0.14.118:6000 -> 10.0.14.118:5060
SIP/2.0 100 Trying
Via: SIP/2.0/UDP proxy-b.com:5060
;branch=z9hG4bKbe6d.619fd995c3fc8764ce5cd9c7be7efeef.1.cs102;received=10.0.14.118;rport=5060
Via: SIP/2.0/UDP proxy-a.com:5060
;rport=5060;branch=z9hG4bKbe6d.10c4c5f001c66b8976214d4aef9f635c.1
Via: SIP/2.0/UDP did.com:5060;received=did.com
;branch=z9hG4bK45f94ed9;rport=5060
Record-Route: <sip:proxy-b.com;lr;did=d18.7a9>
Record-Route: <sip:proxy-a.com;lr>
From: "7654321" <sip:7654321@did.com>;tag=as55c522e1
To: <sip:123456@proxy-a.com>
Call-ID: 67675c7e636d6e773860255316e54779(a)did.com
CSeq: 103 INVITE
Server: proxy
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO,
PUBLISH, MESSAGE
Supported: replaces, timer
Session-Expires: 1800;refresher=uas
Contact: <sip:123456@10.0.14.118:6000>
Content-Length: 0

2020/12/17 10:08:20.937756 10.0.14.118:6000 -> 10.0.14.118:5060
SIP/2.0 180 Ringing
Via: SIP/2.0/UDP proxy-b.com:5060
;branch=z9hG4bKbe6d.619fd995c3fc8764ce5cd9c7be7efeef.1.cs102;received=10.0.14.118;rport=5060
Via: SIP/2.0/UDP proxy-a.com:5060
;rport=5060;branch=z9hG4bKbe6d.10c4c5f001c66b8976214d4aef9f635c.1
Via: SIP/2.0/UDP did.com:5060;received=did.com
;branch=z9hG4bK45f94ed9;rport=5060
Record-Route: <sip:proxy-b.com;lr;did=d18.7a9>
Record-Route: <sip:proxy-a.com;lr>
From: "7654321" <sip:7654321@did.com>;tag=as55c522e1
To: <sip:123456@proxy-a.com>;tag=as147bfa3e
Call-ID: 67675c7e636d6e773860255316e54779(a)did.com
CSeq: 103 INVITE
Server: proxy
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO,
PUBLISH, MESSAGE
Supported: replaces, timer
Session-Expires: 1800;refresher=uas
Contact: <sip:123456@10.0.14.118:6000>
Content-Length: 0

2020/12/17 10:08:20.938593 10.0.14.118:5060 -> proxy-a.com:5060
SIP/2.0 180 Ringing
Via: SIP/2.0/UDP proxy-a.com:5060
;rport=5060;branch=z9hG4bKbe6d.10c4c5f001c66b8976214d4aef9f635c.1
Via: SIP/2.0/UDP did.com:5060;received=did.com
;branch=z9hG4bK45f94ed9;rport=5060
Record-Route: <sip:proxy-b.com;lr;did=d18.7a9>
Record-Route: <sip:proxy-a.com;lr>
From: "7654321" <sip:7654321@did.com>;tag=as55c522e1
To: <sip:123456@proxy-a.com>;tag=as147bfa3e
Call-ID: 67675c7e636d6e773860255316e54779(a)did.com
CSeq: 102 INVITE
Server: proxy
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO,
PUBLISH, MESSAGE
Supported: replaces, timer
Session-Expires: 1800;refresher=uas
Contact: <sip:123456@10.0.14.118:6000;alias=10.0.14.118~6000~1>
Content-Length: 0

2020/12/17 10:08:22.075814 10.0.14.118:6000 -> 10.0.14.118:5060
SIP/2.0 200 OK
Via: SIP/2.0/UDP proxy-b.com:5060
;branch=z9hG4bKbe6d.619fd995c3fc8764ce5cd9c7be7efeef.1.cs102;received=10.0.14.118;rport=5060
Via: SIP/2.0/UDP proxy-a.com:5060
;rport=5060;branch=z9hG4bKbe6d.10c4c5f001c66b8976214d4aef9f635c.1
Via: SIP/2.0/UDP did.com:5060;received=did.com
;branch=z9hG4bK45f94ed9;rport=5060
Record-Route: <sip:proxy-b.com;lr;did=d18.7a9>
Record-Route: <sip:proxy-a.com;lr>
From: "7654321" <sip:7654321@did.com>;tag=as55c522e1
To: <sip:123456@proxy-a.com>;tag=as147bfa3e
Call-ID: 67675c7e636d6e773860255316e54779(a)did.com
CSeq: 103 INVITE
Server: proxy
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO,
PUBLISH, MESSAGE
Supported: replaces, timer
Session-Expires: 1800;refresher=uas
Contact: <sip:123456@10.0.14.118:6000>
Content-Type: application/sdp
Require: timer
Content-Length: 296

2020/12/17 10:08:22.077049 10.0.14.118:5060 -> proxy-a.com:5060
SIP/2.0 200 OK
Via: SIP/2.0/UDP proxy-a.com:5060
;rport=5060;branch=z9hG4bKbe6d.10c4c5f001c66b8976214d4aef9f635c.1
Via: SIP/2.0/UDP did.com:5060;received=did.com
;branch=z9hG4bK45f94ed9;rport=5060
Record-Route: <sip:proxy-b.com;lr;did=d18.7a9>
Record-Route: <sip:proxy-a.com;lr>
From: "7654321" <sip:7654321@did.com>;tag=as55c522e1
To: <sip:123456@proxy-a.com>;tag=as147bfa3e
Call-ID: 67675c7e636d6e773860255316e54779(a)did.com
CSeq: 102 INVITE
Server: proxy
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO,
PUBLISH, MESSAGE
Supported: replaces, timer
Session-Expires: 1800;refresher=uas
Contact: <sip:123456@10.0.14.118:6000;alias=10.0.14.118~6000~1>
Content-Type: application/sdp
Require: timer
Content-Length: 316

2020/12/17 10:08:22.103365 proxy-a.com:5060 -> 10.0.14.118:5060
ACK sip:123456@10.0.14.118:6000;alias=10.0.14.118~6000~1;alias=109.72.216.251~5060~1
SIP/2.0
Via: SIP/2.0/UDP proxy-a.com:5060
;branch=z9hG4bKbe6d.0fc1940efc770391762d7d67094c24f8.0
Via: SIP/2.0/UDP did.com:5060;received=did.com
;branch=z9hG4bK2a5fae72;rport=5060
Route: <sip:proxy-b.com;lr;did=d18.7a9>
Max-Forwards: 70
From: "7654321" <sip:7654321@did.com>;tag=as55c522e1
To: <sip:123456@proxy-a.com>;tag=as147bfa3e
Contact: <sip:7654321@did.com:5060>
Call-ID: 67675c7e636d6e773860255316e54779(a)did.com
CSeq: 102 ACK
User-Agent: proxy
Content-Length: 0

2020/12/17 10:08:22.103877 10.0.14.118:5060 -> 10.0.14.118:6000
ACK sip:123456@10.0.14.118:6000;alias=109.72.216.251~5060~1 SIP/2.0
Via: SIP/2.0/UDP proxy-b.com:5060
;branch=z9hG4bKbe6d.79f351d031912aae585207d2f26d5650.0
Via: SIP/2.0/UDP proxy-a.com:5060
;rport=5060;branch=z9hG4bKbe6d.0fc1940efc770391762d7d67094c24f8.0
Via: SIP/2.0/UDP did.com:5060;received=did.com
;branch=z9hG4bK2a5fae72;rport=5060
Max-Forwards: 70
From: "7654321" <sip:7654321@did.com>;tag=as55c522e1
To: <sip:123456@proxy-a.com>;tag=as147bfa3e
Contact: <sip:7654321@did.com:5060>
Call-ID: 67675c7e636d6e773860255316e54779(a)did.com
CSeq: 102 ACK
User-Agent: proxy
Content-Length: 0
P-K-CSeq-Refresh: 103

2020/12/17 10:08:22.575533 10.0.14.118:6000 -> 10.0.14.118:5060
SIP/2.0 200 OK
Via: SIP/2.0/UDP proxy-b.com:5060
;branch=z9hG4bKbe6d.619fd995c3fc8764ce5cd9c7be7efeef.1.cs102;received=10.0.14.118;rport=5060
Via: SIP/2.0/UDP proxy-a.com:5060
;rport=5060;branch=z9hG4bKbe6d.10c4c5f001c66b8976214d4aef9f635c.1
Via: SIP/2.0/UDP did.com:5060;received=did.com
;branch=z9hG4bK45f94ed9;rport=5060
Record-Route: <sip:proxy-b.com;lr;did=d18.7a9>
Record-Route: <sip:proxy-a.com;lr>
From: "7654321" <sip:7654321@did.com>;tag=as55c522e1
To: <sip:123456@proxy-a.com>;tag=as147bfa3e
Call-ID: 67675c7e636d6e773860255316e54779(a)did.com
CSeq: 103 INVITE
Server: proxy
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO,
PUBLISH, MESSAGE
Supported: replaces, timer
Session-Expires: 1800;refresher=uas
Contact: <sip:123456@10.0.14.118:6000>
Content-Type: application/sdp
Require: timer
Content-Length: 296

2020/12/17 10:08:22.576777 10.0.14.118:5060 -> proxy-a.com:5060
SIP/2.0 200 OK
Via: SIP/2.0/UDP proxy-a.com:5060
;rport=5060;branch=z9hG4bKbe6d.10c4c5f001c66b8976214d4aef9f635c.1
Via: SIP/2.0/UDP did.com:5060;received=did.com
;branch=z9hG4bK45f94ed9;rport=5060
Record-Route: <sip:proxy-b.com;lr;did=d18.7a9>
Record-Route: <sip:proxy-a.com;lr>
From: "7654321" <sip:7654321@did.com>;tag=as55c522e1
To: <sip:123456@proxy-a.com>;tag=as147bfa3e
Call-ID: 67675c7e636d6e773860255316e54779(a)did.com
CSeq: 102 INVITE
Server: proxy
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO,
PUBLISH, MESSAGE
Supported: replaces, timer
Session-Expires: 1800;refresher=uas
Contact: <sip:123456@10.0.14.118:6000;alias=10.0.14.118~6000~1>
Content-Type: application/sdp
Require: timer
Content-Length: 316

2020/12/17 10:08:22.581649 proxy-a.com:5060 -> 10.0.14.118:5060
ACK sip:123456@10.0.14.118:6000;alias=10.0.14.118~6000~1;alias=109.72.216.251~5060~1
SIP/2.0
Via: SIP/2.0/UDP proxy-a.com:5060
;branch=z9hG4bKbe6d.b9c7eeccd4cd7b44f05b173308dbaf0a.0
Via: SIP/2.0/UDP did.com:5060;received=did.com
;branch=z9hG4bK219933f6;rport=5060
Route: <sip:proxy-b.com;lr;did=d18.7a9>
Max-Forwards: 70
From: "7654321" <sip:7654321@did.com>;tag=as55c522e1
To: <sip:123456@proxy-a.com>;tag=as147bfa3e
Contact: <sip:7654321@did.com:5060>
Call-ID: 67675c7e636d6e773860255316e54779(a)did.com
CSeq: 102 ACK
User-Agent: proxy
Content-Length: 0

2020/12/17 10:08:22.582313 10.0.14.118:5060 -> 10.0.14.118:6000
ACK sip:123456@10.0.14.118:6000;alias=109.72.216.251~5060~1 SIP/2.0
Via: SIP/2.0/UDP proxy-b.com:5060
;branch=z9hG4bKbe6d.33626b5695ad4648ba393bc62bed6a8c.0
Via: SIP/2.0/UDP proxy-a.com:5060
;rport=5060;branch=z9hG4bKbe6d.b9c7eeccd4cd7b44f05b173308dbaf0a.0
Via: SIP/2.0/UDP did.com:5060;received=did.com
;branch=z9hG4bK219933f6;rport=5060
Max-Forwards: 70
From: "7654321" <sip:7654321@did.com>;tag=as55c522e1
To: <sip:123456@proxy-a.com>;tag=as147bfa3e
Contact: <sip:7654321@did.com:5060>
Call-ID: 67675c7e636d6e773860255316e54779(a)did.com
CSeq: 102 ACK
User-Agent: proxy
Content-Length: 0
P-K-CSeq-Refresh: 103

2020/12/17 10:08:23.575828 10.0.14.118:6000 -> 10.0.14.118:5060
SIP/2.0 200 OK
Via: SIP/2.0/UDP proxy-b.com:5060
;branch=z9hG4bKbe6d.619fd995c3fc8764ce5cd9c7be7efeef.1.cs102;received=10.0.14.118;rport=5060
Via: SIP/2.0/UDP proxy-a.com:5060
;rport=5060;branch=z9hG4bKbe6d.10c4c5f001c66b8976214d4aef9f635c.1
Via: SIP/2.0/UDP did.com:5060;received=did.com
;branch=z9hG4bK45f94ed9;rport=5060
Record-Route: <sip:proxy-b.com;lr;did=d18.7a9>
Record-Route: <sip:proxy-a.com;lr>
From: "7654321" <sip:7654321@did.com>;tag=as55c522e1
To: <sip:123456@proxy-a.com>;tag=as147bfa3e
Call-ID: 67675c7e636d6e773860255316e54779(a)did.com
CSeq: 103 INVITE
Server: proxy
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO,
PUBLISH, MESSAGE
Supported: replaces, timer
Session-Expires: 1800;refresher=uas
Contact: <sip:123456@10.0.14.118:6000>
Content-Type: application/sdp
Require: timer
Content-Length: 296

2020/12/17 10:08:23.577863 10.0.14.118:5060 -> proxy-a.com:5060
SIP/2.0 200 OK
Via: SIP/2.0/UDP proxy-a.com:5060
;rport=5060;branch=z9hG4bKbe6d.10c4c5f001c66b8976214d4aef9f635c.1
Via: SIP/2.0/UDP did.com:5060;received=did.com
;branch=z9hG4bK45f94ed9;rport=5060
Record-Route: <sip:proxy-b.com;lr;did=d18.7a9>
Record-Route: <sip:proxy-a.com;lr>
From: "7654321" <sip:7654321@did.com>;tag=as55c522e1
To: <sip:123456@proxy-a.com>;tag=as147bfa3e
Call-ID: 67675c7e636d6e773860255316e54779(a)did.com
CSeq: 102 INVITE
Server: proxy
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO,
PUBLISH, MESSAGE
Supported: replaces, timer
Session-Expires: 1800;refresher=uas
Contact: <sip:123456@10.0.14.118:6000;alias=10.0.14.118~6000~1>
Content-Type: application/sdp
Require: timer
Content-Length: 316