Cisco 1003 ISDN Router

Urban Weigl

Hello,

I bought a Cisco 1003 ISDN router on eBay, for the purpose of sharing a UTV Internet connection. It's in perfect condition (not even a scratch!) I checked to make sure that it could be used for this purpose before buying it. However, now that I've got it, I'm a little lost: how do I set it up?

Does anyone have experience with Cisco ISDN routers, how do I set it up to work with UTV internet?

- Urban

The Cigarette Smoking Man

First you have to check that the IOS on the router will run NAT. I think you need 12.0 or above, you can check by doing a "show flash".

After that you'll setup your ethernet interface to something like 192.168.0.1 and then configure your BRI to dialup utv. There's a few articles on it on ciscos website with sample configs:

http://www.cisco.com/warp/public/701/23.html

If you get stuck, do a "show run" from enable mode and paste it in here.

Edit:

After you've done all that you have to set your default route as the Dialer interface, so that all traffic will be sent down your ISDN line. To do that you use the command:

ip route 0.0.0.0 0.0.0.0 Dialer1

You'll should also put an access list on the BRI so that it doesn't just dialup if it senses any network traffic (eg Network Broadcasts).

Kali

You'll should also put an access list on the BRI so that it doesn't just dialup if it senses any network traffic (eg Network Broadcasts).

ip route 192.168.*.0 255.255.255.0 Ethernet0

where * is whatever your local network subnet is.. should do the job?

you don't really need access-lists at all to get anything working.. but disabling external telnet access to the router is something which should be done.

in your internal interface definition:
ip access-group 140 in

and then:
access-list 140 deny tcp any any eq telnet

they're unbeliveably configurable so get stuck in and play around with a few different access-lists to tighten things up a bit..

The Cigarette Smoking Man

I don't think that route will work, if you specify the Ethernet0 as your next hop it won't go anywhere?

(The reason I said 0.0.0.0 0.0.0.0 instead of 192.168.0.0 255.255.255.0 is that it's a stub network, but it shouldn't make any difference either way)

spongebob

Unlike analog where a US fone will plug stright into and Irish socket and work...outta the box...the US for a long time had a different ISDN standard running 56k while we here ran 64k

I would first concentrate on the BRI0 setup and get that to work if poss, stage one involved making a call out , such as to your mobile and answering it. Then add the CHAP stuff and ring the UTV number and pick up an IP over PPP.

The ETH0 (Intranet side) can be sorted out later but if the fecker wont ring out it is all acedemic IMO

Cisco IOS is not user friendly and takes some getting used to.

M

Kali

Originally posted by The Cigarette Smoking Man
I don't think that route will work, if you specify the Ethernet0 as your next hop it won't go anywhere?

(The reason I said 0.0.0.0 0.0.0.0 instead of 192.168.0.0 255.255.255.0 is that it's a stub network, but it shouldn't make any difference either way)

exactly. that route i mentioned is basically just a loopback for the local network... thus the isdn interface won't be initiated at all for local traffic... then the 0.0.0.0 route will equate to "everything bar local network broadcasts and ips"

and if i'm completly wrong on this please say so

spongebob

is to exlplicitly block ports 135 -139 TCP and UDP , both directions , on the ETH0

thats the network chatter port range and you get yourself the beginnings of a firewall that way too.

M

The Cigarette Smoking Man

I'd be going with Mucks way Kali No point in having to log into the router everytime you want to dialup when you could do it automatically. (You can always just hit the power button if you don't want it dialing out)

Gavin

Originally posted by The Cigarette Smoking Man
I'd be going with Mucks way Kali No point in having to log into the router everytime you want to dialup when you could do it automatically. (You can always just hit the power button if you don't want it dialing out)

The router will automaticly connect when it recieves an ip request outside of 192.168.x.y with kali's configuration...

Then just stick ACL's on the BRI0 interface.

Gav

The Cigarette Smoking Man

My fault, I thought he was adding the ip route 192.168.*.0 255.255.255.0 Ethernet0 instead of the ip route 0.0.0.0 0.0.0.0 Dialer1, rather than in addition to it.

Still though, why would you need to add a route to your 192 address when it's directly connected? That should be added automatically to your routing table. If you do a show ip route it should come up something like:

192.168.0.0/24 is subnetted, 1 subnets
C 192.168.0.1 is directly connected, Ethernet0