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Tuesday, October 19, 2010

Troubleshooting 2


RB should have a default route to serial 1/0 (172.16.18.252) on RA. Domain name, DNS, netbios, netbios type, and lease is required. Lab it up if required.



RA
__
no ip dhcp use vrf connected
ip dhcp excluded-address 172.16.18.1 172.16.18.254
!
ip dhcp pool 0
   network 172.16.0.0 255.255.0.0
   domain-name packetsanalyzed.com
   dns-server 172.16.1.250 172.16.2.251
   netbios-name-server 172.16.1.18
   default-router 172.16.18.252 172.16.18.253
   netbios-node-type p-node
   lease 30
!
ip dhcp pool 1
   network 172.16.18.0 255.255.255.0
  default-router 10.0.0.1
!
ip dhcp pool 2
   network 172.16.22.0 255.255.255.0
   dns-server 172.16.22.250 172.16.22.251


interface Serial1/0
 ip address 172.16.18.253 255.255.255.0
 ip address 172.16.18.252 255.255.255.0 secondary
 encapsulation ppp
 peer default ip address dhcp-pool 0
 serial restart-delay 0
 no fair-queue


RB
__


interface FastEthernet0/1
 ip address 10.0.0.250 255.255.255.0
 duplex auto
 speed auto
!
interface Serial1/0
 ip address negotiated
 encapsulation ppp
 serial restart-delay 0
 no fair-queue


do sh ip route

Gateway of last resort is not set

     172.16.0.0/32 is subnetted, 2 subnets
C       172.16.18.253 is directly connected, Serial1/0
C       172.16.18.13 is directly connected, Serial1/0
     10.0.0.0/24 is subnetted, 1 subnets
C       10.0.0.0 is directly connected, FastEthernet0/1
Posted by Packets Analyzed at 6:46 PM
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3 comments:

steve.dibias said...

Without knowing exactly what I can and can't do here this is what I have come up with. Also for clarification purposes my serial interfaces are s2/0

With the default configuration I was pulling an IP of 172.16.0.1

RB(config-if)#do sh ip int br | ex un
Interface IP-Address OK? Method Status Protocol

FastEthernet0/1 10.0.0.250 YES manual up up

Serial2/0 172.16.0.1 YES IPCP up up

The second thing that I notice is that we are excluding the entire range for 172.16.18.0/24, I chose to modify this as follows

no ip dhcp excluded-address 172.16.18.1 172.16.18.254
ip dhcp excluded-address 172.16.18.252 172.16.18.253

Most of what we want is in pool 0 however the pool for this range is 1 so I have added in all of the info from pool 0 to 1 (with the exception of the network which already exists) also the default router is on an entirely different subnet so that also has changed

ip dhcp pool 1
no default-router 10.0.0.1
domain-name packetsanalyzed.com
dns-server 172.16.1.250 172.16.2.251
netbios-name-server 172.16.1.18
default-router 172.16.18.252 172.16.18.253
netbios-node-type p-node
lease 30

One more thing on RA will be to modify the s2/0, otherwise our default route will be pointing to the wrong IP

interface Serial2/0
no ip address 172.16.18.252 255.255.255.0 secondary
no ip address 172.16.18.253 255.255.255.0
ip address 172.16.18.252 255.255.255.0
ip address 172.16.18.253 255.255.255.0 secondary
no peer default ip address dhcp-pool 0
peer default ip address dhcp-pool 1

Assuming no ip route commands we can set the default route via IPCP

RB

int s2/0
ppp ipcp route default

So now let's test this

RA

no ip dhcp excluded-address 172.16.18.1 172.16.18.254
ip dhcp excluded-address 172.16.18.252 172.16.18.253

ip dhcp pool 1
no default-router 10.0.0.1
domain-name packetsanalyzed.com
dns-server 172.16.1.250 172.16.2.251
netbios-name-server 172.16.1.18
default-router 172.16.18.252 172.16.18.253
netbios-node-type p-node
lease 30

interface Serial2/0
no ip address 172.16.18.252 255.255.255.0 secondary
no ip address 172.16.18.253 255.255.255.0
ip address 172.16.18.252 255.255.255.0
ip address 172.16.18.253 255.255.255.0 secondary
no peer default ip address dhcp-pool 0
peer default ip address dhcp-pool 1

RB

Int s2/0
ppp ipcp route default

RB(config-if)#do sh ip int br | ex un
Interface IP-Address OK? Method Status Protocol

FastEthernet0/1 10.0.0.250 YES manual up up

Serial2/0 172.16.18.15 YES IPCP up up



RB(config-if)#do sh ip route
Gateway of last resort is 172.16.18.252 to network 0.0.0.0
172.16.0.0/16 is variably subnetted, 3 subnets, 2 masks
C 172.16.18.252/32 is directly connected, Serial2/0
C 172.16.18.15/32 is directly connected, Serial2/0
S 172.16.0.0/16 [1/0] via 172.16.18.252
10.0.0.0/24 is subnetted, 1 subnets
C 10.0.0.0 is directly connected, FastEthernet0/1
S* 0.0.0.0/0 [1/0] via 172.16.18.252

So I don’t know if this satisfies the requirements or breaks the rules??

Happy labbing!

October 20, 2010 at 11:28 AM
Packets Analyzed said...

Great stuff!

This is the solution I was looking for. The next troubleshooting scenario will include more requirements.

BTW: There was some additional solutions that I am still reviewing that may get added.

Good stuff Steve!

October 20, 2010 at 2:07 PM
steve.dibias said...

Jason, I do enjoy these and seeing what people come up with, some people have very creative solutions that I wouldn't have thought of :P

This is great a great learning experience, so thanks for posting these!

October 21, 2010 at 12:15 AM

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