Shorewall devel - May 2002 - RE: [Shorewall-users] SMTP outbound problem (fwd)

> -----Original Message-----
> From: Tom Eastep [mailto:teastep@shorewall.net]
> Sent: Monday, May 13, 2002 9:05 AM
> To: Steve Herber
> Cc: Shorewall Development
> Subject: Re: [Shorewall-devel] RE: [Shorewall-users] SMTP outbound
> problem (fwd)
> 
> 
> On Mon, 13 May 2002, Steve Herber wrote:
> 
> > I think we should add an FAQ entry for tcp_ecn.
> > I remember Tom giving a good description in one of his many 
> > responses and there is mention of it in the pptp page, but
> > I could not find the response from Tom about different tcp
> > stacks.
> >
> 
> Are you referring to:
> 
> http://www.shorewall.net/pipermail/shorewall-users/2002-May/001226.html 
> maybe? 
> 
That''s the description I would use. Although I might preface the FAQ
with a
short description of an ecn related problem. 

In the case where I had this problem, my customer''s mail server was an
MS
Exchange 5.5/SP4 server running on NT4.0/SP6a. This server was front ended
by a Cisco PIX firewall. What I could never determine was "where" the
packet
was being dropped due to the ecn bit. For all I know, my customers ISP
router could have been dropping it. FWIW: A tcptraceroute to port 25 worked.

Steve Cowles