PROBLEM:
You cannot connect your MS Outlook to the Exchange servers; you get
the error:
"Your Microsoft Exchange Server is
unavailable"
SYMPTOMS:
- You performed the troubleshooting steps outlined here; step A worked, but step B failed.
- You are able to connect from work, but not from home.
- You are using Verizon DSL.
CAUSE:
In response to the MS Blast Worm that spread rapidly across the
Internet on August 11, 2003, numerous ISP's (eg. Verizon, Comcast)
across the country have blocked port 135 to mitigate the spread of
the worm. This worm exploits a vulnerability for the RPC process on
port 135. Unfortunately, this is the same port used by your MS
Outlook and our MS Exchange servers to communicate. As a result, any
users using an ISP which has chosen to block the port are not able
to connect to Exchange and will get the error message mentioned
above.
SOLUTIONS:
There are two solutions:
1) Easiest solution: Ask your ISP to unblock port 135 from their
routers and firewalls. If they're hesitant about unblocking it, ask
them to unblock it only for your IP. We have found that most
business ISPs are doing it for our customers.
2) Use Virtual Private Networking (VPN) to connect to Exchange. This
does involve making changes to your computer and can be
inconvenient. If your ISP refuses to unblock the port, please follow
instructions here to
Setup VPN Access.
Remember, you can always access your entire Microsoft Outlook
mailbox via the web using WebMail - click on "Log In" and then
"Outlook Web Access".