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Port mapping?

jerry.mcrae
Level 1
Level 1

we have a new email mail box that has 172.16.1.44 natted to 67.x.x.6 for incoming traffic - what i need to happen is have all outbound smtp traffic from 172.16.1.32 to also use 67.x.x.6 - doable?

thanks in advance.

3 Replies 3

scottmac
Level 10
Level 10

It's "sorta" doable.

The easiest way is to use an internal DNS where the mail server is referenced by its inernal address.

People external to your domain would get the public address, people inside your domain would get the internal address.

You'd need to change the host settings (no real problem if ou're using DHCP) to use the internal DNS as Primary" and an external DNS as secondary.

Good Luck

Scott

I thnik a simple NAT would do the job wherein you can natt all ip range to single IP address with overlad as a feature . If u you post [ show run ] that would help .

see / rate if this works

tc

vladrac-ccna
Level 5
Level 5

I didnt know if it was possible, so Ive tested it.

config

int s1/0.23

ip ad 172.16.123.1

ip nat out

int fa0/0

ip nat ins

ip nat inside source list 115 interface Serial1/0.23 overload

ip nat inside source static 172.16.10.5 interface Serial1/0.23

!

access-list 115 permit ip 172.16.35.0 0.0.0.255 any

r1#sh ip nat translations

Pro Inside global Inside local Outside local Outside global

icmp 172.16.123.1:4 172.16.35.5:4 172.16.123.2:4 172.16.123.2:4

--- 172.16.123.1 172.16.10.5 --- ---

It works without a problem

Vlad