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Confused about NAT [Auto Vs. Manual] and Static vs. Dynamic

TheGoob
VIP
VIP

Hi

So I am just confused over the concepts, and google is not helping. It recites specifics, but nothing that explains.

So, for example. I have several WAN IPs and several LAN Networks [vlans] and will just be dealing with one.

First, I made a MANUAL Dynamic NAT; x.x.x.180 [WAN IP] to 192.168.1.0 [LAN Network] - - To me, that means associate ANY LAN IP 192.168.1.0/24 with WAN IP x.x.x.180. This works, no matter what IP on the 1.x LAN grabs the correct WAN IP.

Second, I make ACL's allowing for Incoming [WAN to LAN] access: Allow incoming from outside to inside 192.168.1.180 Port 25.

Still did not work. So then I made another manual NAT but static x.x.x.180 to 192.168.1.180. [I did not specify] ports.

 

Now it works, incoming and outgoing mail. But works does not mean works right. How does a NON PORT SPECIFIC 2nd Static NAT make it work? The NAT isn't saying anything about email port 25, so how does it know??

16 Replies 16

TheGoob
VIP
VIP

Oh for the love of!!!

First of all, I rarely run firewall specifics on this type of server as only 2 ports open and ruled by the Cisco FPR but it just occurred to me several months back I fussed around with it and sure enough, 80 was blocked. I unblocked it and bam, Works.

How embarrassing.

Ok. It happens to all of us.

Regards, LG
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