Exchange server not available (wireless)

[leofoe]

I have a Windows 2003 server, also running Exchange 2003. I use a Linksys wireless router for LAN and internet access. Starting Outlook 2003 and getting to my mailbox works OK via a wire. Once connected wireless (local) I have a connection, I can reach the internet but upon opening Outlook I get: Exchange server not available.
What's wrong here? Do I need to open ports on the router? I now only have port 80 open for OWA (Outlook Web Access. This works OK.

[leofoe]

I have WPA enabled. Wireless connection to the router and the internet is OK. IP-adresses are:
Router/default gateway: 192.168.1.1
Exchange server: 192.168.1.2
Clients: range 192.168.1.100 - 192.168.1.110

[leofoe]

I think encryption is OK as I have a connection and I can connect to the internet. So I don't see the point in switching from G to B. The problem must be  a routing issue or maybe a firewall issue.
On the client Norton Personal Firewall is running. But why only when connected wireless?