ASA 5510 rDNS issue with email, help!

Jack Yuen — Mon, 11 Mar 2019 22:12:54 GMT

I am a little stuck on this rDNS issue with the ip/fqdn not matching our PTR entry on the IPS DNS

We have web VPN acces setup on the ASA ethernet public IP address.. ie. 12.244.214.3

for the PTR DNS we have our mail server fqdn set to ie. 12.244.214.5

but all our mail is being sent out thru the ASA using the .3 address, therfore causing issue with the mismatch of the rDNS checks.

we have tried changing the fqdn/ptr to .3 address but that didnt work cause thats the hosting the VPN connection.

how can i redirect all the out going emails to using the .5 address on the block that we own?

thanks

ASA 5510 rDNS issue with email, help!

palomoj — Wed, 25 Jan 2012 23:39:51 GMT

you can either create a 1:1 NAT for your internal mail server or you can create PAT all outbound SMTP whether its coming from your internal mail server or other computers.

1:1 NAT solution - static (inside,outside) 12.244.214.5 192.168.100.5 netmask 255.255.255.255

PAT solution -

access-list SMTP permit tcp any any eq smtp

nat (inside) 25 access-list SMTP

global (outside) 25 12.244.214.5

topic ASA 5510 rDNS issue with email, help! in Network Security

ASA 5510 rDNS issue with email, help!

ASA 5510 rDNS issue with email, help!