Wednesday 22 February 2012

Transparent ZBF, IRB, and VRF troubleshooting.

“Why doesn’t this PING work!?!”
Here is a simple 3 router configuration, well at least it is simple on 2 of the 3 routers. R1 and R3 are configured quite traditionally, but R2 is a bit more involved.
Here is the diagram.
ZBF Transparent VRF R2
Here are the details.
R2 is using a VRF which includes both LAN interfaces. R2 is also acting as a Zone Based Firewall in transparent mode, allowing all ICMP traffic in both directions, as well as SSH from the inside to the outside networks. R2 has a bridged virtual interface in the 10.123.0.0/24 network. All are running OSPF, but pings issued from R2 to the loopbacks of R1 and R3 are failing.
Can you identify why?
Here is the relevant output:

R1#show ip ospf neighbor
Neighbor ID     Pri   State           Dead Time   Address         Interface
3.3.3.3           1   FULL/DR         00:00:39    10.123.0.3      FastEthernet0/0
10.123.0.2        1   FULL/BDR        00:00:32    10.123.0.2      FastEthernet0/0
R1#show ip route ospf
     3.0.0.0/32 is subnetted, 1 subnets
O       3.3.3.3 [110/2] via 10.123.0.3, 00:01:33, FastEthernet0/0

R1#ping 3.3.3.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 60/88/172 ms
R1#ssh -l admin 3.3.3.3
Password: <password>

R3#show ssh
Connection Version Mode Encryption  Hmac         State                 Username
0          1.99     IN   aes128-cbc  hmac-sha1    Session started       admin
0          1.99     OUT  aes128-cbc  hmac-sha1    Session started       admin
%No SSHv1 server connections running.
R3#exit

[Connection to 3.3.3.3 closed by foreign host]
R1#
Now for R2:
R2#show ip ospf neighbor
Neighbor ID     Pri   State           Dead Time   Address         Interface
1.1.1.1           1   FULL/DROTHER    00:00:37    10.123.0.1      BVI1
3.3.3.3           1   FULL/DR         00:00:35    10.123.0.3      BVI1

R2#show ip route ospf

R2#show policy-map type inspect zone-pair
 Zone-pair: zp-in-to-out

  Service-policy inspect : p-in-to-out

    Class-map: c-in-to-out (match-any)
      Match: protocol icmp
        4 packets, 320 bytes
        30 second rate 0 bps
      Match: protocol ssh
        3 packets, 72 bytes
        30 second rate 0 bps
      Inspect
        Packet inspection statistics [process switch:fast switch]
        tcp packets: [4:390]
        icmp packets: [0:50]

        Session creations since subsystem startup or last reset 8
        Current session counts (estab/half-open/terminating) [0:0:0]
        Maxever session counts (estab/half-open/terminating) [2:1:1]
        Last session created 00:02:23
        Last statistic reset never
        Last session creation rate 0
        Maxever session creation rate 3
        Last half-open session total 0

    Class-map: class-default (match-any)
      Match: any
      Drop (default action)
        0 packets, 0 bytes
 Zone-pair: zp-out-to-in

  Service-policy inspect : p-out-to-in

    Class-map: c-out-to-in (match-all)
      Match: protocol icmp
      Inspect
        Packet inspection statistics [process switch:fast switch]
        icmp packets: [0:20]

        Session creations since subsystem startup or last reset 2
        Current session counts (estab/half-open/terminating) [0:0:0]
        Maxever session counts (estab/half-open/terminating) [1:1:0]
        Last session created 00:25:24
        Last statistic reset never
        Last session creation rate 0
        Maxever session creation rate 1
        Last half-open session total 0

    Class-map: class-default (match-any)
      Match: any
      Drop (default action)
        4 packets, 96 bytes

R2#ping 3.3.3.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)

R2# show run
version 12.4
hostname R2
!
ip vrf myvrf
!
class-map type inspect match-any c-in-to-out
 match protocol icmp
 match protocol ssh
class-map type inspect match-all c-out-to-in
 match protocol icmp
!
policy-map type inspect p-in-to-out
 class type inspect c-in-to-out
  inspect
 class class-default
policy-map type inspect p-out-to-in
 class type inspect c-out-to-in
  inspect
 class class-default
!
zone security inside
zone security outside
zone-pair security zp-in-to-out source inside destination outside
 service-policy type inspect p-in-to-out
zone-pair security zp-out-to-in source outside destination inside
 service-policy type inspect p-out-to-in
bridge irb
!
interface FastEthernet0/0
 ip vrf forwarding myvrf
 no ip address
 zone-member security inside
 bridge-group 1
!
interface FastEthernet0/1
 ip vrf forwarding myvrf
 no ip address
 zone-member security outside
 bridge-group 1
!
interface BVI1
 ip vrf forwarding myvrf
 ip address 10.123.0.2 255.255.255.0
!
router ospf 1 vrf myvrf
 router-id 10.123.0.2
 network 0.0.0.0 255.255.255.255 area 0
!
bridge 1 protocol ieee
bridge 1 route ip
end
Here is R3:
R3#show ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
1.1.1.1           1   FULL/DROTHER    00:00:32    10.123.0.1      FastEthernet0/1
10.123.0.2        1   FULL/BDR        00:00:31    10.123.0.2      FastEthernet0/1

R3#show ip route ospf
     1.0.0.0/32 is subnetted, 1 subnets
O       1.1.1.1 [110/2] via 10.123.0.1, 00:29:36, FastEthernet0/1

R3#ping 1.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 76/117/176 ms
R3#
Similar configuration scenarios are included in both our RS and SC workbooks at NB.
Take a moment, and post your ideas on why the PING from R2 is failing, and thanks for taking the time to assist!

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