Outlook Express can no longer send email; telnet to port 25 fails to get a response

A customer has a network of several PCs connected to broadband via a router.

All the PCs have worked perfectly until the other day when one (Windows
2000, Outlook Express 6, AVG anti-virus, no software firewall) has stopped
being able to send email, although it can still receive email. The symptom
is that OE times out on the sending, with no actual error code.

The other PCs on the network, configured to use the same POP and SMTP
servers, work fine.

"telnet smtp-server 25" gives no response for him, whereas when I try it I
get a typical sign-on message. Given that the PC has no firewall (not even
the Windows one, since it's W2K, not XP), I'm not sure what could be
blocking the port 25 traffic just for that PC.

Any suggestions?




Mortimer

In message <46a85d84$0$1602$(E-Mail Removed)>,
Mortimer <(E-Mail Removed)> writes

>A customer has a network of several PCs connected to broadband via a router.
>
>All the PCs have worked perfectly until the other day when one (Windows
>2000, Outlook Express 6, AVG anti-virus, no software firewall) has stopped
>being able to send email, although it can still receive email. The symptom
>is that OE times out on the sending, with no actual error code.
>
>The other PCs on the network, configured to use the same POP and SMTP
>servers, work fine.
>
>"telnet smtp-server 25" gives no response for him, whereas when I try it I
>get a typical sign-on message. Given that the PC has no firewall (not even
>the Windows one, since it's W2K, not XP), I'm not sure what could be
>blocking the port 25 traffic just for that PC.

Can he get www.bbc.co.uk with today's date -- AKA does he have a pipe
to the Internet ?
If he can:
o Check the hosts file
o Check connection properties for the email account in Tools > Accounts
> Chose Account > Properties > Connection tab

If he can't then there is something wrong with his local network
connection to the router or its properties.
--
Tony

"Mortimer" <(E-Mail Removed)> wrote in message
news:46a85d84$0$1602$(E-Mail Removed)...
> A customer has a network of several PCs connected to broadband via a
> router.
>
> All the PCs have worked perfectly until the other day when one (Windows
> 2000, Outlook Express 6, AVG anti-virus, no software firewall) has
> stopped being able to send email, although it can still receive email.
> The symptom is that OE times out on the sending, with no actual error
> code.

Huh? OE normally gives an error code when it times out.

> "telnet smtp-server 25" gives no response for him

Blank screen? Connection timed out?

Does AVG have email filtering, and is it enabled? If so, it probably uses an
LSP (same technique used by personal firewalls) to do outbound email
filtering, and something has gone wrong within it. Uninstalling and
reinstalling AVG might resolve it, but test email before reinstalling - if
it still doesn't work then will need to look deeper.

Alex

In article <46a85d84$0$1602$(E-Mail Removed)>,
Mortimer
(E-Mail Removed) says...
> A customer has a network of several PCs connected to broadband via a router.
>
> All the PCs have worked perfectly until the other day when one (Windows
> 2000, Outlook Express 6, AVG anti-virus, no software firewall) has stopped
> being able to send email, although it can still receive email. The symptom
> is that OE times out on the sending, with no actual error code.

Presumably there is some sort of error message.
>
> The other PCs on the network, configured to use the same POP and SMTP
> servers, work fine.
>
> "telnet smtp-server 25" gives no response for him, whereas when I try it I
> get a typical sign-on message.

Is that by name or number?

"Rob Morley" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) t...
> In article <46a85d84$0$1602$(E-Mail Removed)>,
> Mortimer
> (E-Mail Removed) says...
>> A customer has a network of several PCs connected to broadband via a
>> router.
>>
>> All the PCs have worked perfectly until the other day when one (Windows
>> 2000, Outlook Express 6, AVG anti-virus, no software firewall) has
>> stopped
>> being able to send email, although it can still receive email. The
>> symptom
>> is that OE times out on the sending, with no actual error code.
>
> Presumably there is some sort of error message.

Just OE's "connection timed out to smtp-server". When I said "no error code"
I was really meaning that it doesn't get as far as connecting to the SMTP
server and getting a failure reponse from it such as "invalid SMTP
username/password" (he's accessing his SMTP server from a "foreign"
connection so he needs to authenticate - but this has worked in the past and
still works from other PCs on the network).

>> The other PCs on the network, configured to use the same POP and SMTP
>> servers, work fine.
>>
>> "telnet smtp-server 25" gives no response for him, whereas when I try it
>> I
>> get a typical sign-on message.
>
> Is that by name or number?

By name: I emailed him yesterday to ask him to try by IP address as well,
but I haven't heard back from him yet. He was also going to try uninstalling
AVG in case that had got corrupted and was swallowing the SMTP requests
instead of passing them on to TCP.

Mortimer wrote:
> A customer has a network of several PCs connected to broadband via a router.
>
> All the PCs have worked perfectly until the other day when one (Windows
> 2000, Outlook Express 6, AVG anti-virus, no software firewall) has stopped
> being able to send email, although it can still receive email. The symptom
> is that OE times out on the sending, with no actual error code.
>
> The other PCs on the network, configured to use the same POP and SMTP
> servers, work fine.
>
> "telnet smtp-server 25" gives no response for him, whereas when I try it I
> get a typical sign-on message. Given that the PC has no firewall (not even
> the Windows one, since it's W2K, not XP), I'm not sure what could be
> blocking the port 25 traffic just for that PC.
>
> Any suggestions?
>
>
This can heppen if you have a trojan loaded that has 'borrowed' port 25
for its own purposes (eg: spam mailing) - and AVG may not detect it.

You mightg spo something with tcpview:

http://www.microsoft.com/technet/sys...s/TcpView.mspx

Do some scans

Fire up Internet Explorer and visit http://safety.live.com

Fire up IE or Firefox and visit http://housecall.trendmicro.com/

"Linker3000" <(E-Mail Removed)> wrote in message
news:46abb348$0$15222$(E-Mail Removed)...
> Mortimer wrote:
>> A customer has a network of several PCs connected to broadband via a
>> router.
>>
>> All the PCs have worked perfectly until the other day when one (Windows
>> 2000, Outlook Express 6, AVG anti-virus, no software firewall) has
>> stopped being able to send email, although it can still receive email.
>> The symptom is that OE times out on the sending, with no actual error
>> code.
>>
>> The other PCs on the network, configured to use the same POP and SMTP
>> servers, work fine.
>>
>> "telnet smtp-server 25" gives no response for him, whereas when I try it
>> I get a typical sign-on message. Given that the PC has no firewall (not
>> even the Windows one, since it's W2K, not XP), I'm not sure what could be
>> blocking the port 25 traffic just for that PC.
>>
>> Any suggestions?
> This can heppen if you have a trojan loaded that has 'borrowed' port 25
> for its own purposes (eg: spam mailing) - and AVG may not detect it.
>
> You mightg spo something with tcpview:
>
> http://www.microsoft.com/technet/sys...s/TcpView.mspx
>
> Do some scans
>
> Fire up Internet Explorer and visit http://safety.live.com
>
> Fire up IE or Firefox and visit http://housecall.trendmicro.com/

I'll try that:. It looks as if I'm going to have to visit him - I was trying
initially to solve it at a distance.

I've just heard that he cannot telnet to the SMTP server on port 25 using
the server's IP address as opposed to domain name, so it looks as if it's
not a DNS issue. So it could well be something that is blocking port 25.
Tcpview, Adaware and Spybot, here we come!

"Mortimer" <(E-Mail Removed)> wrote in message
news:46a85d84$0$1602$(E-Mail Removed)...
>A customer has a network of several PCs connected to broadband via a
>router.
>
> All the PCs have worked perfectly until the other day when one (Windows
> 2000, Outlook Express 6, AVG anti-virus, no software firewall) has stopped
> being able to send email, although it can still receive email. The symptom
> is that OE times out on the sending, with no actual error code.
>
> The other PCs on the network, configured to use the same POP and SMTP
> servers, work fine.

Having visited the customer today, I found that some of the tests I'd got
the customer to perform had invalid results, so I'd jumped to the wrong
conclusion.

It *is* possible to telnet to port 25 on the SMTP server (and on others that
I tried). I was even able to establish a session with the server to send an
email, by typing the SMTP protocol commands (EHLO, MAIL FROM, RCPT TO etc).
For some reason, on the customer's PC, the sign-on message doesn't appear
immediately but only when a key is pressed, whereas on my computers, the
message appears immediately, so I didn't tell him to press any key to force
the sign-on message to appear :-(

However OE cannot send email. There's no immediate error message in the
Send/Receive dialogue box, but after a minute you get the pop-up "Failed to
contact SMTP server - Wait / Stop?".

This is with no anti-virus installed (I temporarily removed AVG).

TCPVIEW shows that nothing else is doing anything on port 25. When I telnet
to the server, a TCP connection is established between a random port on the
PC and port 25 on the SMTP server. Intriguingly, when OE does a
Send/Receive, the same connection is established and remains established
until I select Stop on the "Failed to contact" message box. If I
deliberately change the SMTP server to one which is invalid, I get an
immediate failure "Could not find server".

So what could have gone wrong with OE to cause it to establish a TCP
connection with the server but then fail to send the STMP protocol commands.

OE's smtp.log file shows nothing whatsoever when I do a Send/Receiv -
there's just OE's sign-on message "SMTP Log started at <date> <time>".


I wonder if it's all tied up with this fact that telnet is not producing a
sign-on message as soon as the connection is established, but only after the
PC sends some data, equivalent to the keypress in the telnet session.

Any further suggestions?

In article <46abb348$0$15222$(E-Mail Removed)>, Linker3000
(E-Mail Removed) says...

> This can heppen if you have a trojan loaded that has 'borrowed' port 25
> for its own purposes (eg: spam mailing) - and AVG may not detect it.
>
But it's port 25 on the remote machine that matters - the local port
will be whatever high-numbered one the application gets given.

"Rob Morley" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) ...
> In article <46abb348$0$15222$(E-Mail Removed)>, Linker3000
> (E-Mail Removed) says...
>> This can heppen if you have a trojan loaded that has 'borrowed' port 25
>> for its own purposes (eg: spam mailing) - and AVG may not detect it.
>>
> But it's port 25 on the remote machine that matters

Indeed. Linker3000's comment doesn't make any sense.

> the local port will be whatever high-numbered one the application gets
> given.

Actually, applications can choose the local port on an outbound connection,
but they don't usually care so they leave it to the OS (which, as you wrote,
will choose a high-numbered port).

Alex