### Description I am using TOPOS module to hide internal topology. The module strips Via header from INVITE sip message correctly but do not strip from ACK and BYE.

See Sip Traffic section for details.

#### SIP Traffic ``` INVITE sip:79200204544@95.79.44.126:5060 SIP/2.0 Via: SIP/2.0/UDP 35.204.224.219:5060;branch=z9hG4bK6ede.37d0b08c7b0331a435a0943a939a4025.0 Max-Forwards: 70 From: "" sip:testin2@35.228.92.211;tag=S2363F7Qt7eNr To: sip:79200204544@10.164.0.10:5060 Call-ID: cce13277-d70b-1237-a6b5-42010aa60002 CSeq: 2943281 INVITE User-Agent: FreeSWITCH-mod_sofia/1.8.5+git-20190227T164909Z~cb1f3ab6f2~64bit Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, INFO, UPDATE, REGISTER, REFER, NOTIFY Supported: timer, path, replaces Allow-Events: talk, hold, conference, refer Content-Type: application/sdp Content-Disposition: session Content-Length: 352 X-FS-Support: update_display,send_info Remote-Party-ID: sip:"testin2"@35.228.92.211;party=calling;screen=yes;privacy=off Contact: sip:btpsh-5caf4729-2afa-2@35.204.224.219

v=0 o=FreeSWITCH 1554967661 1554967662 IN IP4 35.228.92.211 s=FreeSWITCH c=IN IP4 35.228.92.211 t=0 0 m=audio 26486 RTP/AVP 18 0 8 102 103 4 101 a=rtpmap:18 G729/8000 a=rtpmap:0 PCMU/8000 a=rtpmap:8 PCMA/8000 a=rtpmap:102 SPEEX/8000 a=rtpmap:103 L16/8000 a=rtpmap:4 G723/8000 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-16 a=ptime:20

SIP/2.0 100 Trying Via: SIP/2.0/UDP 35.204.224.219:5060;branch=z9hG4bK6ede.37d0b08c7b0331a435a0943a939a4025.0 From: "" sip:testin2@35.228.92.211;tag=S2363F7Qt7eNr To: sip:79200204544@10.164.0.10:5060 Call-ID: cce13277-d70b-1237-a6b5-42010aa60002 CSeq: 2943281 INVITE Allow: INVITE,ACK,CANCEL,BYE,UPDATE,REGISTER,PRACK,INFO,NOTIFY,REFER,SUBSCRIBE Cisco-Guid: 52032-2942042128-2148574276-299034469 User-Agent: TELES CELLX Plus 20.5.36.1 58216060749209 Content-Length: 0

SIP/2.0 183 Session in Progress Via: SIP/2.0/UDP 35.204.224.219:5060;branch=z9hG4bK6ede.37d0b08c7b0331a435a0943a939a4025.0 From: "" sip:testin2@35.228.92.211;tag=S2363F7Qt7eNr To: sip:79200204544@10.164.0.10:5060;tag=242182414738912437015910463786 Call-ID: cce13277-d70b-1237-a6b5-42010aa60002 CSeq: 2943281 INVITE Allow: INVITE,ACK,CANCEL,BYE,UPDATE,REGISTER,PRACK,INFO,NOTIFY,REFER,SUBSCRIBE Cisco-Guid: 52032-2942042128-2148574276-299034469 Contact: sip:79200204544@95.79.44.126 User-Agent: TELES CELLX Plus 20.5.36.1 58216060749209 Content-Type: application/sdp Content-Length: 175

v=0 o=- 16 1 IN IP4 95.79.44.126 s=- c=IN IP4 95.79.44.126 t=0 0 m=audio 29000 RTP/AVP 4 a=sendrecv a=ptime:1200 a=rtpmap:4 G723/8000 a=fmtp:4 bitrate=6.3;annexa=no

SIP/2.0 180 Ringing Via: SIP/2.0/UDP 35.204.224.219:5060;branch=z9hG4bK6ede.37d0b08c7b0331a435a0943a939a4025.0 From: "" sip:testin2@35.228.92.211;tag=S2363F7Qt7eNr To: sip:79200204544@10.164.0.10:5060;tag=242182414738912437015910463786 Call-ID: cce13277-d70b-1237-a6b5-42010aa60002 CSeq: 2943281 INVITE Allow: INVITE,ACK,CANCEL,BYE,UPDATE,REGISTER,PRACK,INFO,NOTIFY,REFER,SUBSCRIBE Cisco-Guid: 52032-2942042128-2148574276-299034469 Contact: sip:79200204544@95.79.44.126 User-Agent: TELES CELLX Plus 20.5.36.1 58216060749209 Content-Type: application/sdp Content-Length: 175

v=0 o=- 16 2 IN IP4 95.79.44.126 s=- c=IN IP4 95.79.44.126 t=0 0 m=audio 29000 RTP/AVP 4 a=sendrecv a=ptime:1200 a=rtpmap:4 G723/8000 a=fmtp:4 bitrate=6.3;annexa=no

SIP/2.0 200 OK Via: SIP/2.0/UDP 35.204.224.219:5060;branch=z9hG4bK6ede.37d0b08c7b0331a435a0943a939a4025.0 From: "" sip:testin2@35.228.92.211;tag=S2363F7Qt7eNr To: sip:79200204544@10.164.0.10:5060;tag=242182414738912437015910463786 Call-ID: cce13277-d70b-1237-a6b5-42010aa60002 CSeq: 2943281 INVITE Allow: INVITE,ACK,CANCEL,BYE,UPDATE,REGISTER,PRACK,INFO,NOTIFY,REFER,SUBSCRIBE Cisco-Guid: 52032-2942042128-2148574276-299034469 Contact: sip:79200204544@95.79.44.126 User-Agent: TELES CELLX Plus 20.5.36.1 58216060749209 Content-Type: application/sdp Content-Length: 175

v=0 o=- 16 3 IN IP4 95.79.44.126 s=- c=IN IP4 95.79.44.126 t=0 0 m=audio 29000 RTP/AVP 4 a=sendrecv a=ptime:1200 a=rtpmap:4 G723/8000 a=fmtp:4 bitrate=6.3;annexa=no

ACK sip:79200204544@95.79.44.126:5060;transport=udp SIP/2.0 Record-Route: sip:35.204.224.219;lr;ftag=S2363F7Qt7eNr Via: SIP/2.0/UDP 35.204.224.219:5060;branch=z9hG4bK6ede.1e6c3211c8351ad95b4e6ab73b1edb93.0 Via: SIP/2.0/UDP 35.228.92.211;received=10.166.0.2;rport=5060;branch=z9hG4bK5025HQ19BgBve Max-Forwards: 70 From: "" sip:testin2@35.228.92.211;tag=S2363F7Qt7eNr To: sip:79200204544@10.164.0.10:5060;tag=242182414738912437015910463786 Call-ID: cce13277-d70b-1237-a6b5-42010aa60002 Contact: sip:gw+kamailio@35.204.224.219:5060;gw=kamailio;transport=udp CSeq: 2943281 ACK Content-Length: 0

BYE sip:79200204544@95.79.44.126:5060;transport=udp SIP/2.0 Record-Route: sip:35.204.224.219;lr;ftag=S2363F7Qt7eNr Via: SIP/2.0/UDP 35.204.224.219:5060;branch=z9hG4bK3ede.a79e492bc10c8b5d668d6925dd745145.0 Via: SIP/2.0/UDP 35.228.92.211;received=10.166.0.2;rport=5060;branch=z9hG4bK69UyKjjD9r1ea Max-Forwards: 70 From: "" sip:testin2@35.228.92.211;tag=S2363F7Qt7eNr To: sip:79200204544@10.164.0.10:5060;tag=242182414738912437015910463786 Call-ID: cce13277-d70b-1237-a6b5-42010aa60002 CSeq: 2943282 BYE User-Agent: FreeSWITCH-mod_sofia/1.8.5+git-20190227T164909Z~cb1f3ab6f2~64bit Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, INFO, UPDATE, REGISTER, REFER, NOTIFY Supported: timer, path, replaces Reason: Q.850;cause=16;text="NORMAL_CLEARING" Content-Length: 0

SIP/2.0 200 OK Via: SIP/2.0/UDP 35.204.224.219:5060;branch=z9hG4bK3ede.a79e492bc10c8b5d668d6925dd745145.0 Via: SIP/2.0/UDP 35.228.92.211;received=10.166.0.2;rport=5060;branch=z9hG4bK69UyKjjD9r1ea Record-Route: sip:35.204.224.219;lr;ftag=S2363F7Qt7eNr From: "" sip:testin2@35.228.92.211;tag=S2363F7Qt7eNr To: sip:79200204544@10.164.0.10:5060;tag=242182414738912437015910463786 Call-ID: cce13277-d70b-1237-a6b5-42010aa60002 CSeq: 2943282 BYE Allow: INVITE,ACK,CANCEL,BYE,UPDATE,REGISTER,PRACK,INFO,NOTIFY,REFER,SUBSCRIBE Cisco-Guid: 52032-2942042128-2148574276-299034469 Contact: sip:79200204544@95.79.44.126 User-Agent: TELES CELLX Plus 20.5.36.1 58216060749209 Content-Length: 0

```

### Additional Information

* **Kamailio Version** - output of `kamailio -v`

``` version: kamailio 5.1.8 (x86_64/linux) flags: STATS: Off, USE_TCP, USE_TLS, USE_SCTP, TLS_HOOKS, USE_RAW_SOCKS, DISABLE_NAGLE, USE_MCAST, DNS_IP_HACK, SHM_MEM, 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 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

```

* **Operating System**: ``` Linux vp-balancer-dev-01 4.9.0-8-amd64 #1 SMP Debian 4.9.144-3 (2019-02-02) x86_64 GNU/Linux ```