12 Replies Latest reply: Dec 3, 2011 8:46 PM by matrixx333 RSS

    Bug in PT 5.3.2?

    matrixx333

      Hello Everyone,

       

      I am going nuts trying to figure this problem out and I the only explanation that I can come up with is a bug in the 3560 24PS IOS in Packet Tracer.

       

      I have attached my sim to the discussion. What is happening is I have two 3560's on the LAN side of the network (192.168.8.x). If I try to ping 192.168.8.2 or 192.168.8.1 from anything outside the LAN, the ICMP packet gets to the device, but it never gets passed up to Layer 3 for ICMP processing. If I ping the same device on the LAN side, the ICMP packet gets passed up to Layer 3 with no problem. 

       

      I was hoping someone could check my work and confirm that I am not going crazy.

       

      Thank you in advance for any help you may be able to provide.

        • 1. Re: Bug in PT 5.3.2?
          Natraj Babaria

          Hi,

           

          Can you post the topology as i am not having PT on PC and what's the the not working.

           

          Thanks & Regards,

          Natraj Babaria

          • 2. Re: Bug in PT 5.3.2?
            Brian

            1) you have inconsistent mask on the routers, switches, PC and server.  The PC and server are a /245 mask while the routers and switches are a /22 in the 192.168.8.0 network.

             

            2) you do not have an ip default-gateway set on the switches.  The switches need a default gateway set in order to send and receive pings.

             

            Brian

             

            • 3. Re: Bug in PT 5.3.2?
              Martin

              Bugs are always possibility in PT;

              • 4. Re: Bug in PT 5.3.2?
                matrixx333

                Natraj, I have attached an image of the topology:

                 

                topology.JPG

                 

                Brian:

                 

                Thank you for catching my error with the subnet on the PC\Server. That was a mistake I made. The 3560's are MLS devices, which should be performing routing. I setup a gateway of last resort for 192.168.8.2 to point to 192.168.8.9 and a gateway of last resort for 192.168.8.1 to point to 192.168.8.110. Unless I'm missing something, I think the gateway of last resort should handle the routing back to the devices outside the LAN......

                • 5. Re: Bug in PT 5.3.2?
                  Natraj Babaria

                  Hi,

                   

                  Its very difficult to find out problem in this topology without PT and yeah there is a problem with PT. For better result you can use GNS3.

                   

                  Thanks & Regards,

                  Natraj Babaria

                  • 6. Re: Bug in PT 5.3.2?
                    matrixx333

                    Thank you for the reply Martin.....that's what Im suspecting Im running up against here, I just wanted to make sure that I wasn't missing something....and having another pair of eyes look over your work is always good!

                    • 7. Re: Bug in PT 5.3.2?
                      Martin

                      if you want c3560 to do routing, enable ip routing and change subnets sw to router and sw to PC, PC and router are on the same subnet, right ?

                      if yes, then sw between them is just layer 2.

                      think about L3 switch like a router just with more ports.

                      if you want to use L3 sw just replace or remove WG routers

                      • 8. Re: Bug in PT 5.3.2?
                        Vijay Swaminathan

                        Hi Matrix333,

                         

                        In addition to Brain's comment, I also noticed the following

                         

                        The default gateway set on your Laptop 192.168.8.100 should be the IP of the router. Currently it is set to the MLS SVI.. when you set that to IP of the Router then the end to end ping should work.

                         

                        - Vijay

                        • 9. Re: Bug in PT 5.3.2?
                          Brian

                          Matrixx333,

                           

                          In addition to the earlier reported faults, I also noticed the link between the SW and Router was an Access link and not a Trunk link.  As Martin pointed out with the 3560 configured in this way,it is just a Layer 2 switch.  Therefore, it needs the "ip default-gateway" configured.

                           

                          So, there is no bug in PT per say, but rather limited functionality.  If you had a pure Layer 2 switch you would need to have the "ip default-gateway" configured to ping offnet.  The issue is, in PT the 3560 does not allow you to set the "ip default-gateway", the command is just not available.


                          Here are a couple of options:

                           

                          Option #1
                          Keep the same configuration, but replace the 3560 with a 2960.  Configure the 2960 just as the 3560 and add the "ip default-gateway" command on each switch.  Have each switch point to its directly connected router.  Have the PCs, GW be the most direct router, Not the switch.

                           

                          Option#2
                          Keep the 3560, but change the link between the Switch and Router to a /30 subnet, say 192.168.1.0/30 for Switch 1 and 192.168.2.0/30 for Switch 2.  Then run an IGP on the routers, and switches.  You can then let the Switches terminate the VLAN with the SVI port and put the Switches SVI ports, PCs and Server all in the same subnet 192.168.8.0/24.

                           

                          I already setup Option #2, but I am at work and will have to post the solution later.

                           

                          Hope this helps.

                           

                          Brian

                          • 10. Re: Bug in PT 5.3.2?
                            matrixx333

                            Thank you everyone who participated in helping to solve my problem. I neglected to enable ip routing on the 3560's as Martin pointed out.

                             

                            Since then, I have enabled ip routing on the mls devices and I can ping end to end....

                             

                            Thank you again for your help!

                            • 11. Re: Bug in PT 5.3.2?
                              Brian

                              Simply enabling "ip routing" on the two MLS maitland and Colo will not give FULL reachability throughout the network.

                               

                              Take the below outputs from PC.  While you can reach the networks on Site5 and Site4, you cannot ping to the networks on Site2 and Site3.


                              PC>ping 172.16.2.1

                               

                              Pinging 172.16.2.1 with 32 bytes of data:

                              Reply from 172.16.2.1: bytes=32 time=125ms TTL=253
                              Reply from 172.16.2.1: bytes=32 time=79ms TTL=253
                              Reply from 172.16.2.1: bytes=32 time=120ms TTL=253
                              Reply from 172.16.2.1: bytes=32 time=94ms TTL=253

                               

                              Ping statistics for 172.16.2.1:
                                  Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
                              Approximate round trip times in milli-seconds:
                                  Minimum = 79ms, Maximum = 125ms, Average = 104ms

                               

                              PC>ping 172.16.3.1

                               

                              Pinging 172.16.3.1 with 32 bytes of data:

                              Reply from 172.16.3.1: bytes=32 time=109ms TTL=253
                              Reply from 172.16.3.1: bytes=32 time=125ms TTL=253
                              Reply from 172.16.3.1: bytes=32 time=109ms TTL=253
                              Reply from 172.16.3.1: bytes=32 time=125ms TTL=253

                               

                              Ping statistics for 172.16.3.1:
                                  Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
                              Approximate round trip times in milli-seconds:
                                  Minimum = 109ms, Maximum = 125ms, Average = 117ms

                               

                              PC>ping 10.0.5.100

                               

                              Pinging 10.0.5.100 with 32 bytes of data:

                              Request timed out.
                              Reply from 10.0.5.100: bytes=32 time=155ms TTL=125
                              Reply from 10.0.5.100: bytes=32 time=140ms TTL=125
                              Reply from 10.0.5.100: bytes=32 time=140ms TTL=125

                               

                              Ping statistics for 10.0.5.100:
                                  Packets: Sent = 4, Received = 3, Lost = 1 (25% loss),
                              Approximate round trip times in milli-seconds:
                                  Minimum = 140ms, Maximum = 155ms, Average = 145ms

                               

                              PC>ping 10.0.4.100

                               

                              Pinging 10.0.4.100 with 32 bytes of data:

                              Request timed out.
                              Reply from 10.0.4.100: bytes=32 time=125ms TTL=125
                              Reply from 10.0.4.100: bytes=32 time=156ms TTL=125
                              Reply from 10.0.4.100: bytes=32 time=109ms TTL=125

                               

                              Ping statistics for 10.0.4.100:
                                  Packets: Sent = 4, Received = 3, Lost = 1 (25% loss),
                              Approximate round trip times in milli-seconds:
                                  Minimum = 109ms, Maximum = 156ms, Average = 130ms

                               

                              PC>ping 172.16.4.1

                               

                              Pinging 172.16.4.1 with 32 bytes of data:

                              Request timed out.
                              Request timed out.
                              Request timed out.
                              Request timed out.

                               

                              Ping statistics for 172.16.4.1:
                                  Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

                               

                              PC>ping 172.16.5.1

                               

                              Pinging 172.16.5.1 with 32 bytes of data:

                              Request timed out.
                              Request timed out.
                              Request timed out.
                              Request timed out.

                               

                              Ping statistics for 172.16.5.1:
                                  Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

                               

                              PC>tracert 172.16.4.1

                               

                              Tracing route to 172.16.4.1 over a maximum of 30 hops:

                                1   31 ms     31 ms     18 ms     192.168.8.2
                                2   63 ms     62 ms     62 ms     192.168.8.9
                                3   86 ms     94 ms     94 ms     172.16.0.2
                                4   78 ms     78 ms     94 ms     192.168.8.9
                                5   81 ms     110 ms    125 ms    172.16.0.2
                                6   109 ms    125 ms    94 ms     192.168.8.9
                                7   156 ms    125 ms    156 ms    172.16.0.2
                                8   156 ms    171 ms    125 ms    192.168.8.9
                                9   188 ms    171 ms    126 ms    172.16.0.2
                                10   171 ms    172 ms    181 ms    192.168.8.9
                                11   172 ms    218 ms    203 ms    172.16.0.2
                                12   203 ms    203 ms    188 ms    192.168.8.9
                                13   234 ms    250 ms    203 ms    172.16.0.2
                                14   234 ms    234 ms    234 ms    192.168.8.9
                                15   266 ms    234 ms    203 ms    172.16.0.2
                                16   265 ms    219 ms    250 ms    192.168.8.9
                                17   273 ms    312 ms    281 ms    172.16.0.2
                                18   281 ms    297 ms    265 ms    192.168.8.9
                                19   344 ms    312 ms    290 ms    172.16.0.2
                                20   312 ms    297 ms    343 ms    192.168.8.9

                               

                              This is from the server. The Server can ping to networks on Site2 and Site3, but not to networks on Site4 and Site5.

                               

                              SERVER>ping 172.16.2.1

                               

                              Pinging 172.16.2.1 with 32 bytes of data:

                              Request timed out.
                              Request timed out.
                              Request timed out.
                              Request timed out.

                               

                              Ping statistics for 172.16.2.1:
                                  Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

                               

                              SERVER>tracert 172.16.2.1

                               

                              Tracing route to 172.16.2.1 over a maximum of 30 hops:

                                1   32 ms     6 ms      31 ms     192.168.8.1
                                2   49 ms     47 ms     63 ms     192.168.8.110
                                3   78 ms     94 ms     94 ms     172.16.1.2
                                4   78 ms     94 ms     78 ms     192.168.8.110
                                5   116 ms    125 ms    125 ms    172.16.1.2
                                6   125 ms    125 ms    94 ms     192.168.8.110
                                7   141 ms    140 ms    144 ms    172.16.1.2
                                8   96 ms     156 ms    140 ms    192.168.8.110
                                9   171 ms    188 ms    143 ms    172.16.1.2
                                10   172 ms   
                              Control-C
                              ^C
                              SERVER>

                               

                              This mainly due to the static "default" routes.  Try removing the "default" routes and add subnet specific routes or use an IGP.

                               

                              If you wish to terminate the VLAN on the MLS with the use of the SVI ports.  Then use Layer 3 links between the switch and the routers.

                              Again, use an IGP to to provide the route redundancy to enable FULL network wide reachability.

                               

                              Hope this helps.

                               

                              Brian

                              • 12. Re: Bug in PT 5.3.2?
                                matrixx333

                                Brian,

                                 

                                I experienced the loops that you were referencing in your example. Because of laziness, I have just manually updated the static routes on the "internet" routers as needed.

                                 

                                Everything is doing what I need it to do for my purposes.

                                 

                                Thank you again for taking so much time to be as detailed and informative as possible!