Outlook cannot conect to Exchange Server using Comcast

[brandon.berndt]

Hi Everyone,

I am currently using Outlook 2007 and cannot conect to my companies
Microsoft Exchange Server. I use Comcast as my internet service
provider. I am able to use our webclient through IE to do my daily
emails, but its really a pain not to be able to use Outlook. So I am
looking for a fix.

When I travel, I am able to connect from hotels (I am guessing since
they don't have any ports blocked) so I know my account is set up
correctly.

I read about comcast "blocking" ports that MES uses to communicate,
but am not able to find a fix for this. So my questions are:

Is there a way around this?
What other options do I have? (ex. getting an at&t wireless internet
card to use from home)
Any other suggestions/tips/info?

 

[Peter Durkee]

Are you just trying to connect directly to your Exchange server over the
Internet? If so, it's probably your company's firewall that's causing your
problem as much as anything. Your choices of getting Outlook to work are to
either use a VPN and run Outlook through that, or use RPC over HTTP. Check
with your IT department for details.
-Peter

 

[brandon.berndt]

Are you just trying to connect directly to your Exchange server over the
Internet? If so, it's probably your company's firewall that's causing your
problem as much as anything. Your choices of getting Outlook to work are to
either use a VPN and run Outlook through that, or use RPC over HTTP. Check
with your IT department for details.
-Peter

I can connect to microsoft outlook web access vie mail.ourdomain.com/
exchange just fine. What I am trying to do is be able to use my
outlook client (the actually application on my laptop) to connect with
MES to receive/send mail/calender/contacts. I can only use outlook for
other email address that are pop3 not MES, since outlook won't connect
to our exchange server (reportedly because Comcast blocks the port)

 

[Peter Durkee]

I can connect to microsoft outlook web access vie mail.ourdomain.com/
exchange just fine. What I am trying to do is be able to use my
outlook client (the actually application on my laptop) to connect with
MES to receive/send mail/calender/contacts. I can only use outlook for
other email address that are pop3 not MES, since outlook won't connect
to our exchange server (reportedly because Comcast blocks the port)

I guess it's true that Comcast may be blocking one or more of the ports
needed for an Outlook MAPI connection, but the odds are good that your
corporate firewall is blocking them as well. Connecting via the web client
or by POP3 is comparatively simple as they each involve ports that are
almost never blocked. A full MAPI connection involves a number of ports,
some of which are assigned dynamically, so to allow Outlook to connect using
MAPI through your firewall would require opening a huge range of ports, and
is not considered a good practice.

-Peter

 

[Peter Durkee]

I guess it's true that Comcast may be blocking one or more of the ports
needed for an Outlook MAPI connection, but the odds are good that your
corporate firewall is blocking them as well. Connecting via the web client
or by POP3 is comparatively simple as they each involve ports that are
almost never blocked. A full MAPI connection involves a number of ports,
some of which are assigned dynamically, so to allow Outlook to connect
using MAPI through your firewall would require opening a huge range of
ports, and is not considered a good practice.

-Peter

So I finally read the part about it working when you're in hotels, so
obviously your firewall isn't blocking those MAPI ports. The best
workarounds are still a VPN connection or RPC over HTTP.

-Peter

 

[Brian Tillman]

I can connect to microsoft outlook web access vie mail.ourdomain.com/
exchange just fine. What I am trying to do is be able to use my
outlook client (the actually application on my laptop) to connect with
MES to receive/send mail/calender/contacts. I can only use outlook for
other email address that are pop3 not MES, since outlook won't connect
to our exchange server (reportedly because Comcast blocks the port)

Outlook Web Access uses the standard HTTP ports 80 and 443. Whether OWA
works or not has nothing to do with whether Outlook works or not, since they
don't access Exchange by the same method. Peter's correct. It's highly
unlikely that Comcast is blocking any ports because you're not using the
Comcast ports. Comcast blocks specific ports on their own servers and can't
control what ports are available on your company's servers. Your
assumptions are flawed.

 

[brandon.berndt]

Outlook Web Access uses the standard HTTP ports 80 and 443. Whether OWA
works or not has nothing to do with whether Outlook works or not, since they
don't access Exchange by the same method. Peter's correct. It's highly
unlikely that Comcast is blocking any ports because you're not using the
Comcast ports. Comcast blocks specific ports on their own servers and can't
control what ports are available on your company's servers. Your
assumptions are flawed.

Hmm, I see. Then what are possible reasons for this issue? Any fixes?

 

[Milly Staples [MVP - Outlook]]

Ask Comcast or your Exchange mail host - no one here can help you with your personal configuration issues.

--
Milly Staples [MVP - Outlook]

Post all replies to the group to keep the discussion intact. All
unsolicited mail sent to my personal account will be deleted without
reading.

After furious head scratching, Hays Young asked:

| I just upgraded to Outlook 2007, and suddenly I am no longer able to
| connect to my exchange server that is hosted by 4smartphone through
| my Comcast internet. However, if I change the same computer over to
| my AT&T DSL internet it works just fine. What can I go to comcast
| with to ask them to change on their servers??

 

[Sctadlock]

I am having the same issue...there seems to be a problem and RPC over HTTP is
not working either. It did not happen with office 2003 and the "loss" of
connection only happens at home through Comcast. When I change NO settings,
and go to a free wifi spot I can connect no problem. OWA is accessible
always, but I would rather use Outlook. Do they have a fix for 2007 yet that
I may be missing? I found a workaround here:
http://support.microsoft.com/kb/913843/en-us
but I do not have the RPC key in the registry...very frustrating.

 

[Brian Walker]

I had the same issue using an Verizon Aircard via Craddlepoint MBR1000 Router.

I found that it wasn't the router settings at all (after flipping every option available on the router - and there are a ton of them). I found a little check mark in Outlook that resolved my situation. It may work for you as well.

Under the menu

Tools>Options>Mail Setup>Email Accounts>(select the appropriate account from the list)>Change>More Settings>Connection>Exchange Proxy Settings>

Check the box beside "On Fast Networks, connect using HTTP first, then connect using TCP/IP.

Hope this helps.