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New Member

basic configuration question

Coming from the checkpoint world I'm having some difficulty in understanding the pix. Any help would be great.

I have a two pix firewalls in a failover configuration with 6 fast ethernet ports on each firewall. I have two of the interfaces at a security level of 50, two at 25, one at 0 and one at 100.

As the firewall is on an internal network I have no desire to perform any sort of hide nat. I just want to pass the traffic according to access-lists. I'm confused as to what kind of statement I should be using on each interface to pass the traffic without translation to the other interfaces. Should it be nat with an associated access list, some other form of a nat statement, or a static statement? What would be an example?

New Member

Re: basic configuration question


By default the pix will not send traffic to other interfaces that have the same security level. So 1security level 50 interface wont talk to another level 50.

"Interfaces with the same security level cannot communicate with each other. We recommend that every interface have a unique security level. "

Matt A

New Member

Re: basic configuration question

Ok thank you. That is easily fixed but it doesn't answer the original question.

Cisco Employee

Re: basic configuration question

Easiest way to pass traffic from interface to interface is with a static statement, but map the old address to the same address, effectively eliminating NAT.

Let's say you have:

nameif ethernet0 outside security0

nameif ethernet1 inside security100

ip address outside

ip address inside

then to allow traffic from inside to outside without translation then do:

static (inside,outside) netmask

If you then also want to allow traffic from outside to inside, you just need an access-list allowing that traffic in.

New Member

Re: basic configuration question


You can disable NAT on all interfaces:

nat (inside) 0 0 0

nat (???) 0 0 0


No need to disable nat on the "outside" interface (sec0) because traffic from outside will not NAT by default.

Then use ACL on all interfaces to control the traffic.

STATIC is not good for you because you need to configure it on each pair of interfaces. NAT 0 is what you're looking for.


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