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SMPT through PIX 501

hi

I would like to know how i can get a PIX 501 to enable my exchange 2000 server to receive SMTP traffic.

i need a static route & an access list but do not know the best way to do it, the 501 has no DMZ facility and therfore i am even more unsure? can anyone show me how i can set this up.

firewall outside 81.X.X.X
firewall inside   192.168.0.X

exchange 192.168.0.X

regards

brad
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shivsa
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Hello shivsa


thank you for the links but unfortunately doesnt explain in laymens terms how * what i need to do! i thought it should go somehow like this:

static (inside,outside) tcp interface smtp 192.168.0.27 smtp netmask 255.255.255.255 25 0 0

access-list acl_outside_in permit tcp any host 81.X.X.X

access group . . . . . .  .

no fixup protocol smtp 25


What i need is a list how to get the traffice through a 501 to a single exchange server!

brad
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td_miles

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hi td_miles

Thats what I thought but wasnt sure that it was correct, that now gives me peace of mind that I can go ahead and configure a live network! I will try the above and get back to you with the respone.


brad.

Hi brad
I hope that i can give you more help
so for enabling smtp trafic to pass trought the pix you need to do an static traslation and an access-list that permit smtp traffic port 25
so

you must to do some lines as

static (inside,outside) 81.X.X.X 192.168.6.27 netmask 255.255.255.255 0 0
access-list OUTSIDE permit tcp any host 81.x.x.x eq smtp
access-group OUTSIDE in interface outside

hope you luck
td_miles


ze points are all yours !

thank you for the reassurance.

brad
selmrabet

I am guessing that you static entry:

static (inside,outside) 81.X.X.X 192.168.6.27 netmask 255.255.255.255 0 0

is the same as:

static (inside,outside) tcp interface smtp 192.168.0.27 smtp netmask 255.255.255.255 25 0 0

because I assume that the PIX already knows that 81.X.X.X is the TCP interface?

well it works nevertheless, so I will go ahead and award the points to td_miles! If there is a reason for creating the static translation how you have suggested then please post as I would like to know the difference between the two as I am a newb as far as firewalls are concerned.

brad
To answer the question in your last comment, the difference between the two is the IP address that it uses for the outside IP.

In the first example, it uses a specific IP address (in this case 81.X.X.X), in the second example, it uses whatever the IP address of the outside interface is. You might use the first command when your ISP allocates you more than one IP address and the IP address you wish to use for this NAT is not the same as the IP address of the interface. A good reason for using the "interface" keyword, is if the outside interface has a dynamic IP address (eg. it is connected to ADSL) then you won't know the IP address to put in, so you use interface instead.
Hi td_miles


I see i see i see, well thats all clever stuff and would like to thank selmrabet for the post in conjunction with my question, I would also like to clarify your comment td_miles about;

"You might use the first command when your ISP allocates you more than one IP address and the IP address you wish to use for this NAT is not the same as the IP address of the interface"

So lets say's BT provided me with an address range of 100.100.100.1-7 and my gateway was 100.100.100.2 and my PIX e01 was 100.100.100.3, I could use the address 100.100.100.5 (lets say) as the NAT address for my Exchange box? Sill giving me SMTP connectivity through the firewall and vica versa?

brad
there's no reason why you couldn't do that, you just need to setup the NAT and the ACL to make it work.