topic Re: SYN Timeout in Network Security

SYN Timeout

rsatjharman — Fri, 21 Feb 2020 14:25:11 GMT

Hi,

I have an issue where I am sending a Telnet request to a distant server on port 55019 however I get the following response on the ASA5506 log Teardown TCP connection 446446 for outside:Public IP/55019 to inside:192.168.1.10/2639 duration 0:00:30 bytes 0 SYN Timeout. I have replace the Public IP Address with Public IP. The response is expected to be sent to 192.168.1.10. Need some assistance on this, I can ping Public IP however this particular type of traffic is not coming through thus resulting in the SYN Timeout

Re: SYN Timeout

Meheretab Mengistu — Tue, 03 Oct 2017 19:15:35 GMT

Hi,

Is your server listening on TCP port 2639? "Teardown TCP connection..." might be because the port is closed on the server.

HTH,
Meheretab

Re: SYN Timeout

rsatjharman — Tue, 03 Oct 2017 20:24:05 GMT

Hi,

I am not sure why the Port Number is being changed from 55019 as it is supposed to be returning on 55019 I will need to check since the Server would obviously be listening on Port 55019. Perhaps someone can assist and port us in the direction. I tried the packet tracer app and it is dropping the packet so there would be some issue on the change of port number between the outside and inside interace. Would appreciate some help on this.

Re: SYN Timeout

rsatjharman — Fri, 13 Oct 2017 01:41:28 GMT

I have tried using packet tracer and it seems that the packet is getting dropped due to ACL