netdev - Re: TCP RESET after SACK in Kernel 2.6

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Date:	Thu, 16 Oct 2008 01:40:57 -0700 (PDT)
From:	David Miller <davem@...emloft.net>
To:	cs-linuxnet@...warz-online.com
Cc:	linux-net@...r.kernel.org, netdev@...r.kernel.org
Subject: Re: TCP RESET after SACK in Kernel 2.6

From: Christian Schwarz <cs-linuxnet@...warz-online.com>
Date: Thu, 16 Oct 2008 10:36:57 +0200

[ netdev is the place to post if you actually want a
  knowledgable person to look into your problem ]

> We're running a Debian Linux router with masquerading enabled
> to access a customers site.  The customer connection has a lot of
> packet loss, so we receive some TCP SACK-messages.
> 
> Our old system with Debian 3.1 and Kernel 2.4.xx handled this correctly,
> but after upgrading to Debian 4.0 and Kenrel 2.6.26.5, sometimes the
> SACK-queries are answered with a TCP RESET by the kernel.

Without any example tcpdump traces it is impossible for anyone to help
debug this problem.

> Background question: we have the following setup:
> 
>    client host  ->  router w/ masquerading  ->  target host
> 
> When the target host sends a SACK-query, is it the router's job to
> resend the packets or is this the client host's job?

The end node TCP stack does this, the router doesn't do this.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html