I am hosting a Merak e-mail server for our domain example.com. Everything works great accessing the server from outside the network using mail.example.com for ingoing and outgoing servers. However, clients on the same LAN as the mail server get the error "Outlook cannot connect to your outgoing (SMTP) server"
I have to set the Outgoing server to the internal DNS name or internal IP address of the mail server. This really sucks for our laptop users that move in and out of our network. My question is how can I fix this? Users are able to access webmail using mail.example.com even when in the network so I am thinking this is a setting in merak somewhere.
Best Answer
I'm assuming that you're behind NAT, and if so it sounds like your problem is with Hairpin NAT; your router is port-forwarding traffic on port 25 only if it originates on the external interface (which is why it works for external clients). You'll need to either change a setting on your router to allow forwarding traffic that arrives on the internal interface, or try a different router, or set up internal DNS.