Change external IP address on cisco pix 501

I think this should be fairly straighforward, but I'm not that familiar with the Cisco command line interface.  We're moving offices and have been assigned new ip addresses from our ISP.  I need to know the specific commands to configure the PIX to use the new external IP address (and subnet mask, dns, gateway).  

Also, we host a mail server and have several other ports forwarding, do I need to do anything else besides change the external interface IP?
mjordan22Asked:
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Istvan KalmarHead of IT Security Division Commented:
for example:

change the outside address:
ip address outside 192.168.1.1 255.255.255.0

and after:
claer old route
no ip route 0.0.0.0 0.0.0.0 if_address
type new route
ip route 0.0.0.0 0.0.0.0 if_address

write mem
reload


could you show your config?
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mjordan22Author Commented:
Unfortunately I don't have access to the existing config right now. The hardware is on it's way to the new location. I get what you've posted, but what about the new gateway and DNS servers. Don't those need to be changed too?  Thanks!
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Istvan KalmarHead of IT Security Division Commented:
Hi,

gateway:
and after:
claer old route
no ip route 0.0.0.0 0.0.0.0 if_address
type new route
ip route 0.0.0.0 0.0.0.0 if_address

 dns:
dhcpd dns x.x.x.x  interface inside
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mjordan22Author Commented:
Ok got it, but so that I'm
totally clear in this,  let's say this is the new config info;
ip: 1.2.3.4
sub: 255.255.255.0
gw: 1.2.3.1
DNS: 4.2.2.1 and 4.2.2.2

what would the commands look like?
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Boilermaker85Commented:

I would do a show run before you start to make sure you have the interface names and route info correct. Normally you might name your outside interface "outside" using this statement:
:
PIX Version 6.3(5)
interface ethernet0 100full
interface ethernet1 100full
nameif ethernet0 outside security0
nameif ethernet1 inside security100
...
So you first go into config mode
conf t

Enter the interface ip change
ip address outside 1.2.3.4 255.255.255.0  
no route 0.0.0.0 0.0.0.0 old_GW_IP
route 0.0.0.0 0.0.0.0 1.2.3.1
Assuming you are using the Pix for dhcp on the inside and passing clients the DNS info, you would add this:
dhcpd dns 4.2.2.1 4.2.2.2
 
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Istvan KalmarHead of IT Security Division Commented:
sorry my config is a router config...
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mjordan22Author Commented:
Thanks for the help, I'm going to try this this afternoon and I'll let you know if I run into any problems.
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mjordan22Author Commented:
The solution to my problem was a little more intricate than just changing the IP address, but I'm going to split the points for both people who responded.  Thanks for the help!
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