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  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Date:	Sat, 15 Nov 2008 16:52:28 +0100
From:	Willy Tarreau <>
To:	Karl Pickett <>
Cc:	Andi Kleen <>,,
Subject: Re: tcp_tw_recycle broken?

On Sat, Nov 15, 2008 at 10:47:10AM -0500, Karl Pickett wrote:
> On Sat, Nov 15, 2008 at 8:09 AM, Andi Kleen <> wrote:
> > "Karl Pickett" <> writes:
> >>
> >> May I just confirm.. is tcp_tw_reuse NOT dependent on receiving timestamps?
> >
> > The big problem is that both are incompatible with NAT. So if you
> > ever talk to any NATed clients don't use it.
> >
> > -Andi
> >
> > --
> >
> >
> Hmph.  Running the test again - after getting a little sleep -
> timestamps do indeed determine if tw_reuse/recyle work.  I must not
> have let all the tw buckets expire before changing my timestamp
> settings last night.
> Since
> A. I don't want to rely on arbitrary web servers having timestamps
> B. People say it breaks NAT for clients, and the settings are global only,
> I will just set TCP_TIMEWAIT_LEN to 10 seconds and call it a day.

you should increase it a bit. I've encountered occasional issues at 15s,
but none at 20s.

> Sure would be nice if it was a tunable, so only the most heavily
> loaded customers could set it...

Indeed. other OSes (eg Solaris) ship with standard values and let us adjust


To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to
More majordomo info at

Powered by blists - more mailing lists