Wireshark · Wireshark-users: Re: [Wireshark-users] SYN Retransmissions

["Luis EG Ontanon" <luis@xxxxxxxxxxx>]

Usually a SYN is retransmitted at least 3 times.

Dependingon the OS you might or no have parameters to set this aspects
of TCP behaviour.

Usually you have a retransmit timer (Trtx) and an abort timer (Tabrt) to set up.

The SYN will be retransmitted after some time related to Trtx (N *
Trtx + K) as many times as possible until Tabrt expires.

How this is done changes between OSs.

BSDs uses the following sysctl's
  net.inet.tcp.keepinit
  net.inet.tcp.rexmit_{min,slop}

Solaris uses the parameter
   tcp_rexmit_interval_initial

I do not know how this is set-up in Linux or Windows.


On Fri, Jun 27, 2008 at 5:50 PM, Sheahan, John
<John.Sheahan@xxxxxxxxxxxxx> wrote:
> I have a general question about SYN retransmissions.
> I am troubleshooting a problem whereby an initial SYN is sent but unanswered
> so the client sends one SYN retransmission, when that goes unanswered, no
> more SYNs are sent by the client.
>
> Is this normal behavior or can this be tuned?
>
> I would expect (hope) that the client would retransmitt the SYN more than
> once.
>
> thanks
>
> john
> _______________________________________________
> Wireshark-users mailing list
> Wireshark-users@xxxxxxxxxxxxx
> https://wireshark.org/mailman/listinfo/wireshark-users
>
>



-- 
This information is top security. When you have read it, destroy yourself.
-- Marshall McLuhan