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Cisco 2621 Port Address Translation Vs. Network Address Translation

Mohonk asked
Medium Priority
Last Modified: 2012-05-04
We want to successfully NAT specific ports to a internal server ip. For example our exchange 2003 server. Only port 80 53 21 should be Natted through our router to the server.
When we NAT those individual ports through our router it doesnt work. (Cant browse the internet, or send outside emails.)
ip nat inside source static tcp 53 xx.xxx.xxx.xxx 53 extendable
ip nat inside source static udp 53 xx.xxx.xxx.xxx 53 extendable
ip nat inside source static tcp 80 xx.xxx.xxx.xxx 80 extendable
ip nat inside source static tcp 21 xx.xxx.xxx.xxx 21 extendable

When we NAT everything to the server everything works fine. Even when we setup the windows 2003 built in firewall and block everything except the desired ports.

ip nat inside source static xx.xxx.xxx.xxx extendable

This happens on 2003 2000 and XP Pro machines all the same.  
So why would the router not allow the NATting of indivuidual ports?
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