Exchange web mail server couldn't accessing from few ISP
We have recently installed active-active failover with two asa5520. After that we observed that our exchange server not accessing from outside through few ISP, but it can accessed from other few ISP also. Right now we are accessing internet with one ISP.
Static NAT configuration on the Cisco ASA is:
static (inside,outside) 63.219.x.yz 172.16.3.3 netmask 255.255.255.255
Our mail server is Exchange server based. NAT is working other wise we couldn't access the web mail server from any ISP from outside. We couldn't understand what is the problem either it is happening through our ISP or ASA or mail server.