Hi halijenn / experts
I am having ASA for which i have a seperate outbound mail access and the following is configured.The external interface of the firewall is 188.8.131.52.When i send the mail towards outside to @yahoo.com and then see the mail headers in the yahoo.com [i.e when i check the mail in yahoo and click on headers ), i see the Private IP Address of the organization mentioned / listed like "mxpb.akc.com (172.16.10.1)" in the "received from" field .Please let me know if this is normal ?Also , is it configurable on ASA so that it can be changed to the Public IP [ i.e MX Record ] or is it like that this behaviour totally depends on the YAHOO SMTP gateway ??
static (inside,outside) 184.108.40.206 172.16.10.1 netmask 255.255.255.255
where 172.16.10.1 is SMTP Gateway
Currently i dont have the "sh run" of the customer firewall , as soon as i get it i will post u the service-policy as well .However for the time being if u can throw the light on the same , it will be very helpful.
I see in the headers that the private IP's make sense. You can see:
- MBX2 recieved it from MBX1
- MBX1 then gets it back from MBX2
- Exchange recieved it from MBX1
- Yahoo recieved it from your Exchange server
THe 172.x.x.x IPs are related to the internal communication between your servers (Exchange, MBX1 and MBX2) Yahoo does not see the internal IPs as expected. Yahoo sees it from your 67.x.x.x address. But up to this point, your internal email servers have already written the transaction logs in the email header using the IPs they saw (your internal 172.x.x.x ones). So all is normal from what I can see.