Date: Thu, 10 Jan 2002 11:01:58 -0500 (EST) From: freebsd-questions@juicer.orange-carb.org (Colin Henein) To: freebsd-questions@freebsd.org Subject: Q: ADSL connection hangs (not tcpmssfixup) Message-ID: <20020110160158.7247.qmail@mail.orange-carb.org>
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Greetings all question answering types.
I have a question for you regarding some very strange TCP behaviour
I've noticed over the last little while.
I am on ADSL service (magma.ca), and the FreeBSD box is connected
directly to my Nortel 1meg modem. I have an "inside" network as well,
which pretty much only sends and receives web traffic. I have no ports
that open through onto the inside network, so all incoming connection
requests terminate on the FreeBSD box itself.
I have the classic ADSL problem of not being able to get replies back
from certain websites (whether using lynx on the FreeBSD box, or IE on
my powerbook). I also am running an SMTP server (qmail) and have
trouble receiving emails from certain sites.
If I remove the FreeBSD box from the loop and plug my powerbook
straight into the 1meg modem then I can hit all the websites that I
can't hit when I'm routing through FreeBSD. This makes me suspect
either my configuration of FreeBSD (more likely) or the OS itself
(less likely).
I understand the black hole router problem, but an upgrade to
release-4.4 with the default tcpmssfixup option on ppp doesn't solve
the problem. Here is my ppp.conf file:
|magma:
| set redial 30.120 0
| set reconnect 120 9999999
| set device PPPoE:ed1
| set MRU 1492
| set MTU 1492
| set authname #########
| set authkey #########
| set log Phase
| set dial
| set login
| set ifaddr 64.26.169.169 10.0.0.2/0 255.255.255.255
| set timeout 0
| set cd 5
| enable lqr
| set lqrperiod 10
| set crtscts off
The www problem I can get around with proxies, but the SMTP problems
are more serious. I am dropping emails from a few hosts on the floor,
and a few specific mailing list subscribers are having serious
problems. What happens is that inbound SMTP connections hang after my
FreeBSD box sends the 'go ahead to send data' response. Here is a
captured dialog between my mail server (mail.orange-carb.org) and one
of the problematic senders (tomts9-srv.bellnexxia.net):
> 220 mail.orange-carb.org ESMTP^M
< EHLO tomts9-srv.bellnexxia.net^M
> 250-mail.orange-carb.org^M
> 250-PIPELINING^M
> 250 8BITMIME^M
< MAIL FROM:<normand.levert@sympatico.ca>^M
> 250 ok^M
< RCPT TO:<members@hotrak.ca>^M
> 250 ok^M
< DATA^M
> 354 go ahead^M
> 451 timeout (#4.4.2)^M
> [EOF]
As those familiar with Canadian networks might expect, my attempts to
contact anyone technical at bellnexxia's NOC, or sympatico's IS people
have been met with resounding silence.
I desparately need a solution to this that I can implement
myself. Even my own ISP will be hard to convince since they explicitly
will not support anything that isn't Mac/Windows/Linux.
Is this question too specific and low-level for this forum? I can try
to find one of the tech fora to post in, but I'm not sure of the
netiquette on this issue...
Colin
p.s. I should mention up front that I've been using FreeBSD for many
years now, and have a solid understanding of TCP. So if you think you
can help, don't hold back the technical details on my account...
Colin
--
|| when we're little kids maybe we need stories
Colin Henein || to help us go to sleep. but sooner or later we
|| need stories to help us wake up... -- Utah Phillips
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