05-20-2003 10:19 AM - edited 03-02-2019 07:29 AM
Plain and simple I guess. Do I need more than a /30 on a router to telnet to it if it is running NAT?
I have two routers connected by a t1 with a /30 between them. I configured NAT on the LAN side of one, but now I cannot telnet to it I think because it is trying to get to the pc instead of the router. Is this correct?
05-20-2003 10:23 AM
You should be able to telnet from one router to another but if you are trying to telnet from one router to a pc on the remote routers network, then it should not work. If you had more available IP's then you could static NAT a IP to the PC. Then you could telnet from the outside to the PC
05-20-2003 10:42 AM
I still can't telnet to it, but I can ping it.
If there is a pc behind the router with a private address and I were to ping the public address, doesn't the router and NAT forward the ping requests to the pc or does the router respond?
05-20-2003 10:52 AM
If i guess correctly u have the topology as follows
PC---------------R1-----------------------R2
Now you have applied NAT on the lan side that towards the PC.
The network is now the public ip address which you have given in the NAT translation.
If you ping or telnet this public ip address from R2 side, you should be able to ping or telnet.
but if you ping or telnet to the local address which is translated, then you could not succeed in that, coz, you have masked it using the public ip address.
this has nothing to do with /30 mask. you can overload the interface in natting.
-Deepak
05-20-2003 11:40 AM
Just as mentioned, this has nothing to do with a /30 mask. but if you try to telnet into the router with the NATted address, it might not go depending on your NATting configuration. You should realise that the NATted address is not born by any system, unless you are NATting to an interface address. Hence, you will normally not be able to telnet into it. The workaround is to configure Static NAT simultaeneously and redirect port 23 to the router.
05-20-2003 12:21 PM
I believe that this last message is the case. I have NAT'd the one public address and overloaded it and I cannot connect (telnet) to that address on the router.
Could you please explain or give and example of the static NAT and port redirect? Thanks
05-20-2003 12:30 PM
You could configure NATting using the following command
ip nat inside source list 1 interface loopback 0 to nat to an interface
or configure simultaeneously static and dynamic NATing
Check out the following link
http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a0080093f31.shtml
hope it helps
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