183951 - no check for legitimate mail server

Status: RESOLVED INVALID

(MailNews Core :: Networking: SMTP, defect)

Description

[Manolis Stamatogiannakis]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.2.1) Gecko/20021130
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.2.1) Gecko/20021130

Hi,
I use Mozilla on a laptop that moves around several domains.
To avoid setting multiple smtp servers I have set localhost:25 
as the smtp server and forward the connections from this port to 
my preferred smtp server using ssh tunneling.

When the tunnel exists everything is ok. Outgoing mail are sent and
scanned by norton antivirus.

The problem is when no ssh tunnel exists. Then the mail are still sent
but they are eventually lost. You can telnet to port 25 even without 
an ssh tunnel available. Still the connection is closed without being 
able to do anything, and there's no messages printed on screen too (as
one would expect if a mail server was there).

It seems that it is norton antivirus that replies to port 25 because if
I use another port the mails are not scanned when the tunnel exists and
an error is reported when it doesn't exist.

I think that Mozilla should not be fooled that the mail server is there
just because it can open a connection to port 25. It should detect that 
that it is not a real mail server listening if no identification is printed
from the server side upon connection.

Reproducible: Always

Steps to Reproduce:
1.Write a simple program listening to port x, sleeping a few secs and then
closing it.
2.Set localhost:x as the smtp server on mozilla.
3.Send a mail.

Actual Results:  
The mail is sent even though no real mail server exists,
and no mail-server-like reply is given when you telnet
to port 25. Sent mail is lost.

Expected Results:  
Mozilla should check for an identification string from mail server and report an
error if it isn't there. Eg:
220 foo.domain.com ESMTP Sendmail 8.8.8/FOO-ORG/V3; Fri, 6 Dec 2002 20:51
:31 +0200 (EET)

The bug causes loss of data (you *think* the mail is sent, but it is't) but I
don't know if it should be categorized as critical.

Comment 1

[Henrik Gemal]

not much mozilla can do. having a list with valid smtp headers is not an option.