NAT Issue

[ritesh.p]

Hi there,

I've got cisco 2620XM router.i'm configuring NAT on that. MY ISP has give us single(1) Public IP. so using that i want my user to use internet and using the same IP I want my remote user to access my mail server which is in my local LAN. How can I do that using single IP ? Please advice...

Ritesh

[Georg Pauwen]

Hello,

not sure what exactly you mean: do you want the same user on your LAN to access the Internet and to access the mail server on your local LAN ? Or do you want a user on the Internet to access your mail server on your local LAN ?

Regards,

Georg

[anup.anand]

Yes, you can do this.

Check the last configuration on this link.

http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a0080093f31.shtml

hope this is what you were looking for.

[ritesh.p]

Hi Georg,

In my case,My ISP has given me a Single public IP, I want my LAN user to use internet thru NATted IP on router which is given by ISP. Now i've got some remote(Sales Guys) users who r travelling very frequently. They connect internet thru Dial-up to some ISP. Now my remote user wants to access my mail server which is in LAN. So using same IP which is give by me ISP, how can I configure the same. Hope u'll get clear idea on my screnario.

RITESH

[jdesmon]

I think you would want to use the following command:

ip nat pool library 65.222.125.222 65.222.125.222 netmask 255.255.255.224

ip nat inside source list 10 pool library overload

Don't forget to build access-list 10 and permit your inside networks and to put ip ant outside and ip nat inside on the appropriate interfaces.

John

[preddyi]

In 2620XM I am assuming fa0/0 for connecting to local LAN (private address space 192.168.0.x/24)

And Fa0/1 connecting to ISP having public IP(A.B.C.D)

Router LAN ip 192.168.0.1

Mail server IP 192.168.0.10 and port no 25(SMTP)

The config will look like this.

Inteface Fa0/1

ip address A.B.C.D

ip nat outside

Interface Fa0/0

ip address 192.168.0.1

ip nat inside

ip nat inside source list 100 interface fa0/1 overload

ip nat inside static tcp 192.168.0.10 25 interface fa0/1

ip nat inside static udp 192.168.0.10 25 interface fa0/1

ip access-list 100 permit ip 192.168.0.x 0.0.0.255 any