I replaced my Cisco T1 router using the same configuration. I had to restart my router, running CentOS, which hadn't been restarted in a long long time. I think when I did this I lost some of the configuration. I'm trying to get everything back up and running. It seems like Zimbra can send/receive internal mail just fine. It can receive external mail. However, it cannot send any external mail. What configurations should I check on Zimbra and the router?