ICS: Everything works except sending mails

I'm at a friend who uses WLAN to connect his Windows XP SP 2 (Home) laptop
to the Internet. I've setup Internet Connection Sharing (ICS) on his
laptop and connected my Windows XP SP 2 (Pro) laptop with an Ethernet
cable. I can use various Internet services successfully except one: If I
want to send a mail in Outlook the program tells me that no connection
could be established with the mail server. I know it's wrong as I can
receive mails from the mail server successfully. As I've a few accounts in
Outlook I also know that this problem is not related to one mail server.
In fact I can't send any mail currently at all (no matter what account and
mail server I try to use).

I've setup ICS a couple of times before successfully. If there was a
problem the Internet connection normally just didn't work at all. It's the
first time that I see all Internet services working and accessible except
one. Any ideas what could cause the problem? I tried already to switch off
an anti-virus program on my friend's laptop and even shutdown my own
anti-virus program but it didn't help so far.

Boris

Steve
Mon Jun 16 21:49:58 PDT 2008

On Mon, 16 Jun 2008 17:01:33 +0200, Boris <boriss@web.de> wrote:

>I'm at a friend who uses WLAN to connect his Windows XP SP 2 (Home) laptop
>to the Internet. I've setup Internet Connection Sharing (ICS) on his
>laptop and connected my Windows XP SP 2 (Pro) laptop with an Ethernet
>cable. I can use various Internet services successfully except one: If I
>want to send a mail in Outlook the program tells me that no connection
>could be established with the mail server. I know it's wrong as I can
>receive mails from the mail server successfully. As I've a few accounts in
>Outlook I also know that this problem is not related to one mail server.
>In fact I can't send any mail currently at all (no matter what account and
>mail server I try to use).
>
>I've setup ICS a couple of times before successfully. If there was a
>problem the Internet connection normally just didn't work at all. It's the
>first time that I see all Internet services working and accessible except
>one. Any ideas what could cause the problem? I tried already to switch off
>an anti-virus program on my friend's laptop and even shutdown my own
>anti-virus program but it didn't help so far.
>
>Boris

Sending and receiving E-mail usually use different servers (POP3 and
SMTP).

Perhaps your friend's WLAN ISP is blocking your outgoing messages. It
might not allow connections to SMTP servers other than its own, or it
might block port 25.
--
Best Wishes,
Steve Winograd, MS-MVP (Windows Networking)

Please post any reply as a follow-up message in the news group
for everyone to see. I'm sorry, but I don't answer questions
addressed directly to me in E-mail or news groups.

Microsoft Most Valuable Professional Program
http://mvp.support.microsoft.com

Boris
Tue Jun 17 05:09:05 PDT 2008

On Tue, 17 Jun 2008 06:49:58 +0200, Steve Winograd <bc070521m@comcast.net>
wrote:

> [...]Perhaps your friend's WLAN ISP is blocking your outgoing messages.
> It
> might not allow connections to SMTP servers other than its own, or it
> might block port 25.

Meanwhile I tried to connect to port 25 of the SMTP server with telnet.
When I check the TCP/IP connection with netstat I see a SYN_SENT but no
ACK. In fact I see the very same problem on my friend's laptop (as she
doesn't use Outlook though but reads and writes mails in the browser she
never ran into this problem before). Now indeed it seems like that either
the WLAN router or the ISP is somehow blocking port 25 (although I don't
understand why they should do this if everything else is open).

Anyway does anyone know if I can tunnel the connection to the SMTP server
somehow easily? I guess I would need a trustworthy server which I could
connect to via port 80 for example and which would forward messages to the
SMTP server?

Boris

James
Tue Jun 17 05:47:00 PDT 2008


On Tue, 17 Jun 2008 14:09:05 +0200, Boris <boriss@web.de> wrote:

>Anyway does anyone know if I can tunnel the connection to the SMTP server
>somehow easily? I guess I would need a trustworthy server which I could
>connect to via port 80 for example and which would forward messages to the
>SMTP server?

What's wrong with using your ISP's smtp server?



Jim.

Boris
Tue Jun 17 07:28:44 PDT 2008

On Tue, 17 Jun 2008 14:47:00 +0200, James Egan <jegan@jegan.com> wrote:

> On Tue, 17 Jun 2008 14:09:05 +0200, Boris <boriss@web.de> wrote:
>
>> Anyway does anyone know if I can tunnel the connection to the SMTP
>> server
>> somehow easily? I guess I would need a trustworthy server which I could
>> connect to via port 80 for example and which would forward messages to
>> the
>> SMTP server?
>
> What's wrong with using your ISP's smtp server?

I'm not sure what you mean. I'm trying to use my own SMTP servers as I
always do. The ISP my friend uses seems to block port 25 though. Thus
trying to establish a connection to my own SMTP servers doesn't work.
Meanwhile I found out that two of the SMTP servers I use also provide
another port. After updating my Outlook configuration I can send again
mails via these two SMTP servers. Anyway it's an annoyance of course to
change port numbers because of the ISP.

Boris

Steve
Tue Jun 17 07:26:00 PDT 2008

On Tue, 17 Jun 2008 14:09:05 +0200, Boris <boriss@web.de> wrote:

>On Tue, 17 Jun 2008 06:49:58 +0200, Steve Winograd <bc070521m@comcast.net>
>wrote:
>
>> [...]Perhaps your friend's WLAN ISP is blocking your outgoing messages.
>> It
>> might not allow connections to SMTP servers other than its own, or it
>> might block port 25.
>
>Meanwhile I tried to connect to port 25 of the SMTP server with telnet.
>When I check the TCP/IP connection with netstat I see a SYN_SENT but no
>ACK. In fact I see the very same problem on my friend's laptop (as she
>doesn't use Outlook though but reads and writes mails in the browser she
>never ran into this problem before). Now indeed it seems like that either
>the WLAN router or the ISP is somehow blocking port 25 (although I don't
>understand why they should do this if everything else is open).
>
>Anyway does anyone know if I can tunnel the connection to the SMTP server
>somehow easily? I guess I would need a trustworthy server which I could
>connect to via port 80 for example and which would forward messages to the
>SMTP server?
>
>Boris

You're welcome.

Whose SMTP server are you using? They might allow connection on a
different port. For example, smtp.comcast.net and smtp.gmail.com can
use port 587.

Or, you can configure your E-mail program to use your friend's ISP's
SMTP server when you connect to his network.
--
Best Wishes,
Steve Winograd, MS-MVP (Windows Networking)

Please post any reply as a follow-up message in the news group
for everyone to see. I'm sorry, but I don't answer questions
addressed directly to me in E-mail or news groups.

Microsoft Most Valuable Professional Program
http://mvp.support.microsoft.com