Why does the SonicWall router not function properly for serving on WAN failover?
Posted on 2010-08-24
We have had 2 internet connections installed, from 2 different ISP’s, for redundancy on our company router, which is a SonicWall TZ 210. It is set up with static IP’s for both WAN interfaces, and we are using Dynamic DNS to point our DNS hostname at whichever connection is functioning. That part is operating fine. When the primary ISP goes down, the secondary kicks in, and we can surf the internet just fine. Both ISP connections are business connections and allow serving. I have been able to connect to the router over HTTPS, from either one of them, from outside the network. However, I noticed our services (like e-mail, etc.) do not work when switched over to the secondary connection. (That is, it does not receive mail. You can’t connect to the server from outside. Etc.) I thought it was something to do with the mail server, but I can’t connect to other services that are inside the network, so I started to wonder if the SonicWall was set up right.
Under NAT policies, I have noticed it says “WAN Primary IP” in the rules for the services we are trying to use. So, it would seem these public server policies are not set up to allow these services on the secondary WAN. Does this make sense to those of you who know SonicWall? How can we change the configuration, so that it will automatically work when the router changes over to the secondary ISP? Will it function properly, if I just create a second set of public server rules, when it is running on the secondary connection? Your help is much appreciated in advance. Let me know if more information is required.