2 Replies Latest reply on Nov 22, 2018 4:26 AM by time81

    SN2700 mgmt0 offline / arp cache ?

    time81

                Hi,

       

      we have 2 brand new SN2700 100G Switches. It shipped with Onyx and since the beginning one of them was acting weird on the Management Interface. Even after upgrading to latest version 8190, the switch is rebooted and not pingable, BUT if i start pinging anything from serial connection, the gateway or the second device, the network connecticity is restored.

       

      I ping 10.0.100.100 -t and get no answer from the switch. If i then go on the serial and ping 10.0.254.254, or 10.0.100.101 and the switch begins to be available from my admin host again. Network guys checked the other switch where the mgmt0 is connected to, and point to maybe ARP problems ? Anything else i can do to make it stable ?

      The second switch worked fine out of the box, im not sure whats wrong with that device.

       

      Best regards

       

      Tim

        • Re: SN2700 mgmt0 offline / arp cache ?
          abulak91

          Hi Tim,

           

          Can you share the output of:

          # show interface mgmt0

          # show interface mgmt0 configured

          # show ip route

           

          Please recreate the issue and try the following:

          Connect to the switch using the console, and run the following command:

          # tcpdump -i mgmt0 arp or icmp

          After this and while tcpdump is on start a ping from the remote host.

           

          Are you seeing the remote host ARP or ICMP echo requests ?

            • Re: SN2700 mgmt0 offline / arp cache ?
              time81

              Hi,

               

              So, we tried reverting to factory defaults, switched LAN Cables and LAN Ports. Its still faulty.

              It is NOT pingable from outside until i start pinging from the switch to other machines (10.0.100.146)

              tcpdump ARP is getting more and more AFTER i used ping from console. Before it was rather low. Weird behaviour.

               

               

              mx4 [standalone: master] # mx4 [standalone: master] # show interfaces mgmt0

              Interface mgmt0 status:

                Comment         :

                Admin up        : yes

                Link up         : yes

                DHCP running    : no

                IP address      : 10.0.100.145

                Netmask         : 255.255.0.0

                IPv6 enabled    : yes

                Autoconf enabled: no

                Autoconf route  : yes

                Autoconf privacy: no

                DHCPv6 running  : yes (but no valid lease)

                IPv6 addresses  : 1

               

               

                IPv6 address:

                  fe80::526b:4bff:fef4:fd30/64

               

               

                Speed           : 1000Mb/s (auto)

                Duplex          : full (auto)

                Interface type  : ethernet

                Interface source: bridge

                MTU             : 1500

              lines 1-23   HW address      : 50:6B:4B:F4:FD:30

               

               

                Rx:

                  748655546  bytes

                    7397224  packets

                          0  mcast packets

                          0  discards

                          0  errors

                          0  overruns

                          0  frame

               

               

                Tx:

                  3503019  bytes

                    26117  packets

                        0  discards

                        0  errors

                        0  overruns

                        0  carrier

                        0  collisions

                        0  queue len

               

               

              lines 22-44/44 (END) mx4 [standalone: master] # sh interfaces mgmt0 configured

               

               

              Interface mgmt0 configuration:

                Comment         :

                Enabled         : yes

                DHCP            : no

                DHCP Hostname   : yes

                Zeroconf        : no

                IP address      : 10.0.100.145

                Netmask         : 255.255.0.0

                IPv6 enabled    : yes

                Autoconf enabled: no

                Autoconf route  : yes

                Autoconf privacy: no

                DHCPv6 enabled  : yes

                IPv6 addresses  : 0

                Speed           : auto

                Duplex          : auto

                MTU             : 1500

               

               

              mx4 [standalone: master] # show ip route

               

               

              Flags:

                F: Failed to install in H/W

                B: BFD protected (static route)

                i: BFD session initializing (static route)

                x: protecting BFD session failed (static route)

               

               

              VRF Name default:

                ------------------------------------------------------------------------------

              --------

                Destination     Mask            Flag   Gateway         Interface      Source 

                AD/M  

                ------------------------------------------------------------------------------

              --------

                default         0.0.0.0                10.0.254.254    mgmt0          static 

                1/1   

                10.0.0.0        255.255.0.0            0.0.0.0         mgmt0          direct 

                0/0   

               

              mx4 [standalone: master] # mx4 [standalone: master] # tcpdump -i mgmt0 arp

              tcpdump: verbose output suppressed, use -v or -vv for full protocol decode

              listening on mgmt0, link-type EN10MB (Ethernet), capture size 262144 bytes

              11:42:41.187479 ARP, Request who-has 10.0.40.170 tell 10.0.100.201, length 46

              11:42:41.414540 ARP, Request who-has 10.0.40.115 tell 10.0.254.254, length 46

              11:42:41.423851 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

              11:42:41.911195 ARP, Request who-has 10.0.10.200 tell 10.0.40.135, length 46

              11:42:42.414526 ARP, Request who-has 10.0.40.115 tell 10.0.254.254, length 46

              11:42:42.423809 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

              11:42:43.376184 ARP, Request who-has 10.0.220.222 tell 10.0.220.3, length 46

               

              mx4 [standalone: master] # ping 10.0.254.254

              PING 10.0.254.254 (10.0.254.254) 56(84) bytes of data.

              --- 10.0.254.254 ping statistics ---

              33 packets transmitted, 0 received, 100% packet loss, time 32000ms

               

               

              mx4 [standalone: master] # ping 10.0.100.145

              PING 10.0.100.145 (10.0.100.145) 56(84) bytes of data.

              64 bytes from 10.0.100.145: icmp_seq=1 ttl=64 time=0.045 ms

              64 bytes from 10.0.100.145: icmp_seq=2 ttl=64 time=0.047 ms

              64 bytes from 10.0.100.145: icmp_seq=3 ttl=64 time=0.046 ms

              64 bytes from 10.0.100.145: icmp_seq=4 ttl=64 time=0.047 ms

              64 bytes from 10.0.100.145: icmp_seq=5 ttl=64 time=0.045 ms

              64 bytes from 10.0.100.145: icmp_seq=6 ttl=64 time=0.045 ms

               

               

              AFTER pinging itself and the other maschine (10.0.100.146) suddenly ping works from outside remote host and ARP works more.

               

              mx4 [standalone: master] # tcpdump -i mgmt0 arp

              tcpdump: verbose output suppressed, use -v or -vv for full protocol decode

              listening on mgmt0, link-type EN10MB (Ethernet), capture size 262144 bytes

              11:45:43.400435 ARP, Request who-has 10.0.40.205 tell 10.0.254.254, length 46

              11:45:43.415670 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

              11:45:43.670091 ARP, Request who-has 10.0.10.200 tell 10.0.34.105, length 46

              11:45:43.694971 ARP, Request who-has 10.0.10.200 tell 10.0.34.105, length 46

              11:45:44.400438 ARP, Request who-has 10.0.40.205 tell 10.0.254.254, length 46

              11:45:44.415638 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

              11:45:45.400293 ARP, Request who-has 10.0.40.205 tell 10.0.254.254, length 46

              11:45:45.415544 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

              11:45:46.419348 ARP, Request who-has 10.0.40.115 tell 10.0.254.254, length 46

              11:45:46.438702 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

              11:45:46.462978 ARP, Request who-has 10.0.10.200 tell 10.0.34.105, length 46

              11:45:47.419341 ARP, Request who-has 10.0.40.115 tell 10.0.254.254, length 46

              11:45:47.431649 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

              11:45:48.419348 ARP, Request who-has 10.0.40.115 tell 10.0.254.254, length 46

              11:45:48.431642 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

              11:45:48.449022 ARP, Request who-has 10.0.115.20 tell 10.0.100.170, length 46

              11:45:48.761626 ARP, Request who-has 10.0.254.254 tell 10.0.117.200, length 46

              11:45:49.403327 ARP, Request who-has 10.0.40.205 tell 10.0.254.254, length 46

              11:45:50.403320 ARP, Request who-has 10.0.40.205 tell 10.0.254.254, length 46

              11:45:50.415558 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

              11:45:51.403313 ARP, Request who-has 10.0.40.205 tell 10.0.254.254, length 46

              11:45:51.415546 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

              11:45:52.415634 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46

              11:45:52.438487 ARP, Request who-has 10.0.216.184 tell 10.0.110.135, length 46

              11:45:53.427496 ARP, Request who-has 10.0.40.155 tell 10.0.254.254, length 46