asked on

Frame relay (lab setup). Users can no longer access internet

Ok, I have 2 routers connected back to back. Initially, I was running PPP encapsulation between them . And users on both networks could ping the internet. Everything was great.

Just recently, I set up frame relay between the two routers instead of the PPP. It is not the typcal frame relay setup, since its using a back to back serial. My problem is users in 192.168.2.0 cant even get an IP from my DHCP server anymore. None of the clients in 192.168.2.0 can even ping RouterB. Yet 192.168.2.1 (router B) can ping everywhere.

Here is a diagram of the network
http://mvpbaseball.cc/ee.jpg

Here is my sh run from RouterA (192.168.1.40)
http://mvpbaseball.cc/routera.txt

Here is my sh run from RouterB (192.168.2.1)
http://mvpbaseball.cc/routerb.txt

What is set wrong? Users in the 192.168.2.0 network cant even get an IP. Yet, Router A can ping Router B's interfaces fine.
Thanks!

SOLUTION

celsmk

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

Dr-IP

You probably should add this to one of the routers serial configuration too “frame-relay switching”. I know I have needed it to run frame relay across back to back routers via a crossover T1, so you may also need it for back to back routers via a crossover serial interface.

Also I’d remove RIP, and Replace it with EIGRP, as it’s a considerable more robust dynamic routing protocol than RIP.

router eigrp 10
redistribute connected
redistribute static
network 192.168.0.0
no auto-summary

ASKER CERTIFIED SOLUTION

Dr-IP

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

Dr-IP

PS Except one on the router connected to the internet, the rest of the routes will be learned dynamically.

dissolved

ASKER

Ok thanks guys. So the gateway of last resort (0.0.0.0 0.0.0.0 etc) should only be placed in routers that are NOT connected to the internet????

celmsk, I will try that map command now thanks. I already have ip helper address in there though, hmm.

dr ip: thanks i will try the frame-relay switching command

dissolved

ASKER

ok, I tried

Router(config-subif)#frame-relay map ip 192.168.1.98 101 broadcast
FRAME-RELAY INTERFACE-DLCI command should be used on point-to-point interfaces
Router(config-subif)#

But I didnt try the frame-relay switching command. What does it entail?
thanks!

Dr-IP

Just add it to one of the serial interfaces.

Also what do you get when you do a "sh frame-relay pvc"

dissolved

ASKER

I know that LMI is inactive since I have my frame setup this way (as stated here by Cisco): http://www.cisco.com/warp/public/125/frbacktoback.html
Is that a correct assumption?

Anyway, here it is on router B:
Router#sh frame-relay pvc

PVC Statistics for interface Serial0 (Frame Relay DTE)

Active Inactive Deleted Static
Local 0 0 0 1
Switched 0 0 0 0
Unused 0 0 0 0

DLCI = 101, DLCI USAGE = LOCAL, PVC STATUS = STATIC, INTERFACE = Serial0.1

input pkts 6495 output pkts 6238 in bytes 940709
out bytes 726190 dropped pkts 0 in pkts dropped 0
out pkts dropped 0 out bytes dropped 0
in FECN pkts 0 in BECN pkts 0 out FECN pkts 0
out BECN pkts 0 in DE pkts 0 out DE pkts 0
out bcast pkts 5197 out bcast bytes 667050
pvc create time 1d03h, last time pvc status changed 1d03h

--------------------------------
Also, I gave this command in router B. Is this correct ( i wont be able to test it until tomorrow)

Router(config)#int s0.1 point-to-point
Router(config-subif)#frame-relay switching
Router(config)#

Thanks Dr IP!

Dr-IP

It looks like the protocol is up and passing traffic, so you probably have a routing issue like I thought. As for the frame relay command, that's so you can get LMI active like in the real world. I see Cisco recommends putting it in the root config, but I have always stuck it on the primary interface, it probably will work on the sub interface to, but I am not sure of that one, but it should not hurt anything if it's there too.

http://www.cisco.com/warp/public/125/frbacktoback_hybrid.html

Dr-IP

Tests to check basic routing

From router A

Ping router B serial interface

Ping router B Ethernet interface

From router B

Ping router A serial interface

Ping router A Ethernet interface

dissolved

ASKER

Ok everything pings and responds ok. It did prior to any configurations as well. It's just the clients that are having trouble on the 192.168.2.0 network. hmmmm

Dr-IP

Remove the access list from that routers Ethernet interface.

dissolved

ASKER

Yea thats whats weird. The e0 of router B (192.168.2.1) can ping anywhere fine

It's just the hosts behind it that cant. And they are statically assigned IPs. It may be the ACLs. I'll try that.

When you get a chance, could you elaborate on the default routes more and where to place them? My setup has been working great (when using ppp between the two routers). I set a gateway of last resort on both routers and enabled ip classless. WOrked like a charm.
thanks!

Dr-IP

Default routes, or in proper router nomenclature, routes of last resort, generally point towards the next router, that is unless they are connected to multiple routers, then it’s usually to towards the attached router with the greatest link speed followed by the shortest path towards the core.

But as always in the router world general rules don’t always apply, like when you add an edge router to a large network to allow for Internet access. Then ever thing will ultimately end up having their routes of last resort pointed towards it regardless of link speed. Also there are times the shortest path is chosen over link speed, but now we are getting into performance tuning.

There is a hierarchy of route types by the way, directly connected, static routes, and dynamic. And when there are two matches of the same route type, i.e. 10.10.10.0 255.255.255.0 or 10.0.0.0 255.0.0.0, for the destination 10.10.10.10, the best match is used, in this case 10.10.10.0 255.255.255.0.

dissolved

ASKER

Thanks for the explanation. I'm going to give the ACL thing a try. I have a feeling thats the problem. Especially since router B can ping anywhere.
Thanks!

dissolved

ASKER

It was the ACL. Works great now. I took off the frame-relay switching command (to see what would happen) and everything still worked. Whats the frame-relay switching command do?

Thank you for the help fellas

Dr-IP

The “frame-relay switching” command with the “frame-relay intf-type dce” command will make the router act like a frame relay switch. That way you can get LMI enabled. As for what was wrong with the access list, you forgot to add a permit any. An access list without it, only allows what is expressly permitted, and since you had nothing permitted, all LAN traffic was blocked.

Router1#show frame-relay pvc
PVC Statistics for interface Serial0 (Frame Relay DCE)

Active Inactive Deleted Static
Local 1 0 0 0
Switched 0 0 0 0
Unused 0 0 0 0

DLCI = 101, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0

input pkts 207 output pkts 239 in bytes 15223
out bytes 14062 dropped pkts 0 in FECN pkts 0
in BECN pkts 0 out FECN pkts 0 out BECN pkts 0
in DE pkts 0 out DE pkts 0
out bcast pkts 17 out bcast bytes 3264
PVC create time 00:11:32, last time PVC status changed 00:11:32
Router1#show frame-relay lmi
LMI Statistics for interface Serial0 (Frame Relay DCE) LMI TYPE = CISCO
Invalid Unnumbered info 0 Invalid Prot Disc 0
Invalid dummy Call Ref 0 Invalid Msg Type 0
Invalid Status Message 0 Invalid Lock Shift 0
Invalid Information ID 0 Invalid Report IE Len 0
Invalid Report Request 0 Invalid Keep IE Len 0
Num Status Enq. Rcvd 72 Num Status msgs Sent 71
Num Update Status Sent 0 Num St Enq. Timeouts 0
Router1#

dissolved

ASKER

Thanks!!