Re: [SR-Users] nathelper: ping options over tcp

Hello, Thanks for this feedback. Here the description of the issue I am trying to solve. I use already tcp_keepalive. Call flow is: UACs --> Nat device --> Kamailio Transport protocol is TLS. Kamailio sends TCPs keepalive (tcp_keepalive option) to the softphone located behind the nat devices in order to prevent disconnection due to network inactivity. In most cases I have the expected behavior, I do not have any problems. I think somes NAT devices don't properly handle TCPs keepalive because they close the connection after TCP keepalives. I have always this issue with NAT devices using VSS-Monitoring protocol. A network capture shows: - Kamailio sends a tcp keepalive - The NAT device sends a tck keepalive ACK to Kamailio with a new filed : vss-monitoring Frame 70: 62 bytes on wire (496 bits), 62 bytes captured (496 bits) Linux cooked capture Internet Protocol Version 4, Src: x.x.x.x, Dst: x.x.x.x Transmission Control Protocol, Src Port: 13178, Dst Port: 443, Seq: 2752, Ack: 6214, Len: 0 *VSS-Monitoring ethernet trailer, Source Port: 0* *Src Port: 0* - Kamailio received then a TCP from the NAT device that notifies the closure of the connection. Frame 73: 87 bytes on wire (696 bits), 87 bytes captured (696 bits) Linux cooked capture Internet Protocol Version 4, Src: x.x.x.x, Dst: x.x.x.x Transmission Control Protocol, Src Port: 13178, Dst Port: 443, Seq: 3436, Ack: 6214, Len: 31 Secure Sockets Layer TLSv1.2 Record Layer: Alert (Level: Warning, Description: Close Notify) Content Type: Alert (21) Version: TLS 1.2 (0x0303) Length: 26 Alert Message Level: Warning (1) Description: Close Notify (0) - After a FIN ACK sent to Kamailio by the NAT device, a new tcp three-way handshake is made again. Sometimes, I have this issue during the connection establishment that cause a problem of sending or receiving SIP messages (for examples 200 OK and ACK). The advantage of the SIP ping options is a bidirectional traffic through NAT. I think in this case, my issue will be solved. Regards Abdoul OSSENI 2017-04-05 12:48 GMT+02:00 Daniel-Constantin Mierla &lt;miconda(a)gmail.com <mailto:miconda@gmail.com>>: Hello, nathelper module does ping OPTIONS only for UDP. For tcp/tls, there is transport layer keepalive: - https://www.kamailio.org/wiki/cookbooks/5.0.x/core#tcp_keepalive <https://www.kamailio.org/wiki/cookbooks/5.0.x/core#tcp_keepalive> What is the problem you are trying to solve with this? Maybe there are some other options for it. Cheers, Daniel On 31.03.17 13:03, Abdoul Osséni wrote: -- Daniel-Constantin Mierla www.twitter.com/miconda <http://www.twitter.com/miconda> -- www.linkedin.com/in/miconda <http://www.linkedin.com/in/miconda> Kamailio Advanced Training - May 22-24 (USA) - www.asipto.com <http://www.asipto.com> Kamailio World Conference - May 8-10, 2017 - www.kamailioworld.com <http://www.kamailioworld.com>