cisco 2501 NAT 1

[raaudia4]

can any one help me with this problem.I like to connect my cisco 2501 router to a cable modem.I have obtained an ip address through cable's dhcp server and transferred that ip to the routers ethernet interface, this router is also running nat.From the first router I attach a serial cable to my other 2501 router which is my internal network.(in case you are wOndering why I've attached two routers back to back, each router only has 1 ethernet interface). The problem I am having
is I cannot get to the internet.I can ping all the way to where CABLE comes into the interface and that is as far as I can go.The ip address that I am natting to is the same as the ethernet interface where cable comes in.(Didn't want to resort to a linksys
router) please help.
Thanx in advance

 

[mlien]

Hi Rbaxter1,
Can you show use what your configuration like for both of your router? I ran into the problem before. Luckily, I have 2514 router, it gives me 2 ethernet port. The following is the configuration on my router. I use my ethernet 0 connect with cable modem. Serial connect to my 2501 router. So, it can be apply to your situation. Back to Back connection of your two 2501 routers.

version 11.2
no service password-encryption
no service udp-small-servers
no service tcp-small-servers
!
hostname Router
!
!
ip nat inside source list 1 interface Ethernet0 overload
!
interface Ethernet0
description Direction connection to Cable modem
ip address 24.108.**.** 255.255.255.0(Address provide by my ISP)
no ip directed-broadcast
ip nat outside
no cdp enable
!
interface Ethernet1
description Direct connection to Catalyst Switch 1912
ip address 192.168.1.65 255.255.255.240(My private Network)
ip nat inside
!
interface Serial0
description Direction connection to Router 2501
ip address 192.168.1.17 255.255.255.240
ip nat inside
no fair-queue
clockrate 56000
!
interface Serial1
no ip address
shutdown
!
router rip
network 24.0.0.0
network 192.168.1.0
!
ip classless
ip route 0.0.0.0 0.0.0.0 24.108.33.1(This is IP default-gateway address from your service provider, you can otain those information from your computer)
access-list 1 permit 192.168.1.0 0.0.0.255
!
!
line con 0
line aux 0
line vty 0 4
login
!
end

 

[kcbell]

If you have a static IP like Rbaxter's situation then your two 2501 back to back will work just fine. I think you need to update your outside router iamge to 12.1 then you can use "ip address dhcp" to get the ip from your isp. The key is image 12.1. After that you'll be happy NATTING & PATTING!

 

[raaudia4]

Thanks for the infoe guys, but I am still unable to get to the internet using my routers. My configuration is as follows:

R1>
e0 ip ad 24.x.x.x 255.255.252.0 (ip add obtained by cable)
s1 ip add 192.a.2.2. 255.255.255.0

R2>
e0 ip add 192.a.1.1 255.255.255.0
s1 ip add 192.a.2.1

I've static nat my computer's ip address to that of the cable ip address obtained. My protocol is ospf with a default route pointing to 24.x.x.x I've even issued the command default information originate always.

stumped

 

[Tres]

one thing to also check is that you set the speed and duplex on the router connected to the cable modem...

I ran into this with auto-neg...

Just a thought...

 

[chooser]

I am also trying to setup NAT on a Cisco 806 or 2514 router I have both. I would like to utilize the 806 for this though. I have 2 ethernet ports available. What I am looking to do is have the interface that is connected to the cable modem pull the DHCP from my ISP. My current ISP is starting to rotate thier IP addresses now and I dont want to have to configure it everytime they change them. Has anyone setup either of these routers with Cox Communications or a similar type provider? Does anyone have a config that would get me started? I have been searching everywhere for some sort of white paper to get me going on truly understanding NAT but so far have been unable to obtain one.

 

[jgercken]

Make sure your IOS supports NAT. In early 11 you had to pay for those services with the IP plus pack. You would think that if it weren't available the command would fail but stranger things have happened.

----------------------------------------
Wassabi Pop Tarts! Write Kellogs today!

 

[chooser]

I am running 12.2 and I know it supports NAT with the current image. I am getting really frustrated because I tried playing with the configs from above and nothing is working. I cant find enough info on NAT out on the net or even at bookstores. I was just hoping someone would have been through the same scenario I have been through and that they would be able to explain what I am doing wrong. I am in class now but when I get home I will post my configs and possibly that will help someone to pick at it. Or if anyone knows where I can look as far as finding the info myself that would be greatly appreciated as well. Thanks.

 

[raaudia4]

I will be trying this config "nat on a stick" will let you know if it works.

http://www.cisco.com/warp/public/556/12.html#1

 

[kcbell]

chooser: Try the following. If it does not work, give me your email address. Then I send you the my config file that I know is working on my 3101.

10.1.1.2 is your computer.

interface Ethernet0
ip address 10.1.1.1 255.255.0.0
ip access-group 101 in
no ip directed-broadcast
ip nat inside

interface Ethernet1
ip address dhcp
no ip directed-broadcast
no ip proxy-arp
ip nat outside

ip nat inside source static tcp 10.1.1.2 80 interface Ethernet1 80

Try and learn, try and learn!

 

[chooser]

Maybe I am not so gifted hahaha. Maybe I should start from scratch. right now I have about 5 different configs that I have tried on this thing and so far nogo on any of them. The funny thing is when I got the 806 it came configured for DHCP & NAT. I copied that original config but had problems with it right away. The one thing I will say is that it worked (well sort of) it would pull all my info from my provider which was great and it would pass that info on to whatever machines I had on my network that requested it via DHCP, but about 2 minutes later I would totally go down. I couldnt ping the internet at all I could only ping my gateway. Here is the config that came out of the box...Ohh and I did try putting these configs back in and I cant even get it to do what it was doing before. Thanks in advance.

no parser cache
no service single-slot-reload-enable
no service pad
service timestamps debug uptime
service timestamps log uptime
service password-encryption
!
hostname Router
!
logging rate-limit console 10 except errors
!
ip subnet-zero
ip dhcp excluded-address 10.10.10.1
!
ip dhcp pool CLIENT
import all
network 10.10.10.0 255.255.255.0
default-router 10.10.10.1
!
no ip dhcp-client network-discovery
! lcp max-session-starts 0
!
!
!
interface Ethernet0
ip address 10.10.10.1 255.255.255.0
ip nat inside
no cdp enable
hold-queue 32 in
!
interface Ethernet1
ip address dhcp
ip nat outside
no cdp enable
!
ip nat inside source list 102 interface Ethernet1 overload
ip classless
ip http server
!
access-list 102 permit ip 10.10.10.0 0.0.0.255 any
!
line con 0
exec-timeout 120 0
stopbits 1
line vty 0 4
exec-timeout 0 0
login local
!
scheduler max-task-time 5000
end

 

[Guest_imported]

You need to set the mac address on the e1 int to clone the mac of your NIC card.
to do this i can email you a step by step on how to get the router running, now i cannot get to the router from my pc. and cant get to the pc from router.

but i can get to any valid ip with my router so this will get you "almost" there.

Lightspeed@columbus.rr.com email me and i will send you my directions.

 

[Guest_imported]

I have only one 2501 and want to make NAT cant it be done?? or do i have to use software??

 

[jeter]

NAT will work on 1 router. Do you have an internet connection now on the router? Jeter@LasVegas.com
Fisher CCNA,(Routing)