Martijn de Munnik:
>
> On Jan 20, 2010, at 9:28 PM, Victor Duchovni wrote:
>
> > On Wed, Jan 20, 2010 at 03:22:56PM -0500, Wietse Venema wrote:
> >
> >> The broken router then throws away the bytes with higher sequence
> >> numbers than 14233.
> >>
> >> Workaround: turn off window scaling support on the sender's kernel.
> >
> > This problem is sufficiently common, that on Linux MTAs I always add:
> >
> > net.ipv4.tcp_window_scaling = 0
> I'm running Solaris 10 x86 and I did
>
> sudo ndd -set /dev/tcp tcp_wscale_always 0
>
> before I did this the value was 1. After I did this I flushed the
> queue but the messages stay stuck in the queue with the same
> problem. I'm not sure this is the right kernel parameter for
> Solaris?
You can do
ndd /dev/tcp \?
to find out what parameters are supported. On my Solaris9 and
Solaris10 test boxes it is called tcp_wscale_always.
According to Solaris10 documentation:
When this parameter is enabled, which is the default setting
[since Solaris10], TCP always sends a SYN segment with the
window scale option, even if the window scale option value is
0.
So, please make another recording and report if setting this to 0
causes Solaris to stop sending "wscale 0" options.
If the sender does not send a wscale option, then the receiver
is not supposed to send a wscale option, either. Your tcpdump
recording should confirm that.
> /etc/system has no specific setting for tcp, so everything is
> default Solaris 10.
>
> Wietse, the broken router you mentioned, could that be a Cisco
> PIX on the receivers site?
I maintain no list of CISCO PIX firewall bugs.
It can also be a router at your end. Never exclude that possibility.
> Jan 20 22:58:43 stevie.youngguns.nl postfix/smtp[18765]: [ID 197553
> mail.info] 8A5553BA0C: enabling PIX workarounds: disable_esmtp
> delay_dotcrlf for mx2.amsterdam.nl[145.222.14.10]:25
That's a PIX bug workaround for the fact that their engone parses
only one packet at a time and therefore misses SMTP commands
and <CR><LF>.<CR>LF> when these sit across packet boundaries.
Wietse
