Outbound NAT Choices
warmbowski last edited by
Hello. I am looking for some advice on selecting between two configurations for an outbound NAT situation. I have an email server with an internal IP address of 192.168.0.8.
Currently it uses a dedicated VIP (CARP) of X.X.X.27 when receiving email (and other email related connections). This inbound connection is set up as a port forward:
If Proto Ext. port range NAT IP Int. port range
WAN TCP 25 (SMTP) 192.168.0.8 (ext.: X.X.X.27) 25 (SMTP)
Unfortunately, my email server is still set up to use the interface IP address of X.X.X.26 for outbound connections (i.e. sending email). This gets me into some trouble with email servers that compare the HELO address (.26) to the DNS resolved address (.27).
I noticed that I may have two choices for configuring the outbound connections to use X.X.X.27. Please tell me which you think would be the better way between these two:
Manual Outbound NAT Rule:
Interface Source SrcPrt Dest DestPrt NATAddress NATPort StaticPort
WAN 192.168.0.8/32 * * * X.X.X.27 * NO
Interface External IP Internal IP
WAN X.X.X.27/32 192.168.0.8
Things to note:
X.X.X.27 will be dedicated to the email server IP address and no other internal IP address will share it.
I am already using manual outbound NAT mainly to map my primary LAN (192.168.0.0/24) to the default interface IP address (X.X.X.26) and also to map my secondary LAN (192.168.100.0/24) to a VIP (PARP) IP address (X.X.X.30). This email server falls within the primary LAN. I am oblivious to the difference between a PARP and a CARP address and where I can and cannot use each type.
Thanks for any input.