Re: [PATCH 1/1] tcp: Wrong timeout for SYN segments

From: Eric Dumazet
Date: Fri Aug 31 2012 - 09:25:45 EST


On Fri, 2012-08-31 at 14:48 +0200, Alexander Bergmann wrote:

> Hi Eric!
>
> I've also changed the Documentation file. As usual, comments are welcome!
>
>
> Alex
>
>
> From 848f34ce27f65401940ae98e0b2d395888d3986d Mon Sep 17 00:00:00 2001
> From: Alexander Bergmann <alex@xxxxxxxxxx>
> Date: Fri, 31 Aug 2012 14:31:00 +0200
> Subject: [PATCH 1/1] tcp: Increase timeout for SYN segments
>
> Commit 9ad7c049 changed the initRTO from 3secs to 1sec in accordance to
> RFC6298 (former RFC2988bis). This reduced the time till the last SYN
> retransmission packet gets sent from 93secs to 31secs.
>
> RFC1122 is stating that the retransmission should be done for at least 3
> minutes, but this seems to be quite high.
>
> "However, the values of R1 and R2 may be different for SYN
> and data segments. In particular, R2 for a SYN segment MUST
> be set large enough to provide retransmission of the segment
> for at least 3 minutes. The application can close the
> connection (i.e., give up on the open attempt) sooner, of
> course."
>
> This patch increases the value of TCP_SYN_RETRIES to the value of 6,
> providing a retransmission window of 63secs.
>
> The comments for SYN and SYNACK retries have also been updated to
> describe the current settings. The same goes for the documentation file
> "Documentation/networking/ip-sysctl.txt".
>
> Signed-off-by: Alexander Bergmann <alex@xxxxxxxxxx>
> ---

Thanks for your patience and followup, this seems good to me !

Acked-by: Eric Dumazet <edumazet@xxxxxxxxxx>



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