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Help with a L3 Switch

alexten1983
Level 1
Level 1

Hello all I have a L3 switch where I can ping same ip address from deferent vlans and then same subnet ip but different ip address I can only ping from one vlan. It was working before but now its not.

SinaiSwitchDown#ping 192.168.1.10 source vlan20

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.10, timeout is 2 seconds:
Packet sent with a source address of 10.230.36.253
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms

SinaiSwitchDown#ping 192.168.1.10 source vlan10

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.10, timeout is 2 seconds:
Packet sent with a source address of 192.168.1.253
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms

SinaiSwitchDown#ping 192.168.1.105 source vlan10

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.105, timeout is 2 seconds:
Packet sent with a source address of 192.168.1.253
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms

SinaiSwitchDown#ping 192.168.1.105 source vlan20

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.105, timeout is 2 seconds:
Packet sent with a source address of 10.230.36.253
.....
Success rate is 0 percent (0/5)

But from the 192.168.1.105 I can ping anything

C:\Users\sinai 2560>ping 192.168.1.1

Pinging 192.168.1.1 with 32 bytes of data:
Reply from 192.168.1.1: bytes=32 time<1ms TTL=64
Reply from 192.168.1.1: bytes=32 time<1ms TTL=64
Reply from 192.168.1.1: bytes=32 time<1ms TTL=64
Reply from 192.168.1.1: bytes=32 time<1ms TTL=64

Ping statistics for 192.168.1.1:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum = 0ms, Average = 0ms

C:\Users\sinai 2560>ping 10.230.36.1

Pinging 10.230.36.1 with 32 bytes of data:
Reply from 10.230.36.1: bytes=32 time=2ms TTL=63
Reply from 10.230.36.1: bytes=32 time=1ms TTL=63
Reply from 10.230.36.1: bytes=32 time=1ms TTL=63
Reply from 10.230.36.1: bytes=32 time=1ms TTL=63

Ping statistics for 10.230.36.1:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 1ms, Maximum = 2ms, Average = 1ms

C:\Users\sinai 2560>ping 10.230.36.253

Pinging 10.230.36.253 with 32 bytes of data:
Reply from 10.230.36.253: bytes=32 time=1ms TTL=255
Reply from 10.230.36.253: bytes=32 time=1ms TTL=255
Reply from 10.230.36.253: bytes=32 time=1ms TTL=255
Reply from 10.230.36.253: bytes=32 time=2ms TTL=255

Ping statistics for 10.230.36.253:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 1ms, Maximum = 2ms, Average = 1ms

C:\Users\sinai 2560>ping 192.168.1.253

Pinging 192.168.1.253 with 32 bytes of data:
Reply from 192.168.1.253: bytes=32 time<1ms TTL=255
Reply from 192.168.1.253: bytes=32 time=1ms TTL=255
Reply from 192.168.1.253: bytes=32 time=1ms TTL=255
Reply from 192.168.1.253: bytes=32 time=1ms TTL=255

Ping statistics for 192.168.1.253:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum = 1ms, Average = 0ms

C:\Users\sinai 2560>ping 192.168.1.10

Pinging 192.168.1.10 with 32 bytes of data:
Reply from 192.168.1.10: bytes=32 time<1ms TTL=128
Reply from 192.168.1.10: bytes=32 time<1ms TTL=128
Reply from 192.168.1.10: bytes=32 time<1ms TTL=128
Reply from 192.168.1.10: bytes=32 time<1ms TTL=128

Ping statistics for 192.168.1.10:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 0ms, Maximum = 0ms, Average = 0ms

C:\Users\sinai 2560>ping 10.230.36.10

Pinging 10.230.36.10 with 32 bytes of data:
Reply from 10.230.36.10: bytes=32 time=1ms TTL=62
Reply from 10.230.36.10: bytes=32 time=1ms TTL=62
Reply from 10.230.36.10: bytes=32 time=1ms TTL=62
Reply from 10.230.36.10: bytes=32 time=1ms TTL=62

Ping statistics for 10.230.36.10:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 1ms, Maximum = 1ms, Average = 1ms

What could be the problem?

11 Replies 11

SOHAN HEGDE
Level 1
Level 1

Hello,

you need to enable routing between SVI's. configure "ip routing" command on L3 switch..

it is. its only some ip's from same subnet im not able to ping.

Hello Alex,

From logs which you pasted in appear that you can ping 192.168.1.10& 192.168.1.105 from vlan 10 whose IP is 192.168.1.253 i.e same subnet

However you cannot ping  192.168.1.105 from vlan 20 whose ip is 10.230.36.253 i.e different subnet. so i am suspecting ip routing not enabled.

When you try to reach vlan 20 from machine 192.168.1.105  does it get routed via this L3 switch or some other device. can you provide traceroute to validate the same.

What about

SinaiSwitchDown#ping 192.168.1.10 source vlan20

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.10, timeout is 2 seconds:
Packet sent with a source address of 10.230.36.253
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms

SinaiSwitchDown#ping 192.168.1.10 source vlan10

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.10, timeout is 2 seconds:
Packet sent with a source address of 192.168.1.253
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/1 ms

SinaiSwitchDown#sh ip route
Codes: C - connected, S - static, R - RIP, M - mob
       D - EIGRP, EX - EIGRP external, O - OSPF, I
       N1 - OSPF NSSA external type 1, N2 - OSPF N
       E1 - OSPF external type 1, E2 - OSPF extern
       i - IS-IS, su - IS-IS summary, L1 - IS-IS l
       ia - IS-IS inter area, * - candidate defaul
       o - ODR, P - periodic downloaded static rou

Gateway of last resort is 192.168.1.1 to network 0

     10.0.0.0/24 is subnetted, 1 subnets
C       10.230.36.0 is directly connected, Vlan20
C    192.168.1.0/24 is directly connected, Vlan10
S*   0.0.0.0/0 [1/0] via 192.168.1.1

the .10 and .105 are connected to same switch.

Hi

have you enabled ip routing command? also ip default-gateway should be disabled. 

Can you execute, show ip int brief and share the outputs, thanks. 




>> Marcar como útil o contestado, si la respuesta resolvió la duda, esto ayuda a futuras consultas de otros miembros de la comunidad. <<

Sorry , Yes ip routing command was done. It dose not show up when I do sh run but if I do no ip routing then it dose show up. There is no ip default gateway.

SinaiSwitchDown#sh ip int bri
Interface              IP-Address      OK? Method Status                Protocol
Vlan1                  unassigned      YES manual administratively down down
Vlan10                 192.168.1.253   YES manual up                    up
Vlan11                 10.1.10.253     YES manual administratively down down
Vlan12                 192.168.12.253  YES manual administratively down down
Vlan20                 10.230.36.253   YES manual up                    up
FastEthernet1          10.1.10.1       YES manual down                  down
GigabitEthernet1/1     unassigned      YES unset  up                    up
GigabitEthernet1/2     unassigned      YES unset  up                    up
GigabitEthernet1/3     unassigned      YES unset  up                    up
GigabitEthernet1/4     unassigned      YES unset  up                    up
GigabitEthernet1/5     unassigned      YES unset  up                    up
GigabitEthernet1/6     unassigned      YES unset  up                    up
GigabitEthernet1/7     unassigned      YES unset  up                    up
GigabitEthernet1/8     unassigned      YES unset  down                  down
GigabitEthernet1/9     unassigned      YES unset  down                  down
GigabitEthernet1/10    unassigned      YES unset  up                    up
GigabitEthernet1/11    unassigned      YES unset  down                  down
GigabitEthernet1/12    unassigned      YES unset  up                    up
GigabitEthernet1/13    unassigned      YES unset  up                    up
GigabitEthernet1/14    unassigned      YES unset  up                    up
GigabitEthernet1/15    unassigned      YES unset  up                    up
GigabitEthernet1/16    unassigned      YES unset  up                    up
GigabitEthernet1/17    unassigned      YES unset  down                  down
GigabitEthernet1/18    unassigned      YES unset  up                    up
GigabitEthernet1/19    unassigned      YES unset  up                    up
GigabitEthernet1/20    unassigned      YES unset  up                    up
GigabitEthernet1/21    unassigned      YES unset  up                    up
GigabitEthernet1/22    unassigned      YES unset  up                    up
GigabitEthernet1/23    unassigned      YES unset  up                    up
GigabitEthernet1/24    unassigned      YES unset  up                    up
GigabitEthernet1/25    unassigned      YES unset  down                  down
GigabitEthernet1/26    unassigned      YES unset  down                  down
GigabitEthernet1/27    unassigned      YES unset  down                  down
GigabitEthernet1/28    unassigned      YES unset  down                  down
GigabitEthernet1/29    unassigned      YES unset  down                  down
GigabitEthernet1/30    unassigned      YES unset  down                  down
GigabitEthernet1/31    unassigned      YES unset  down                  down
GigabitEthernet1/32    unassigned      YES unset  down                  down
GigabitEthernet1/33    unassigned      YES unset  down                  down
GigabitEthernet1/34    unassigned      YES unset  down                  down
GigabitEthernet1/35    unassigned      YES unset  down                  down
GigabitEthernet1/36    unassigned      YES unset  down                  down
GigabitEthernet1/37    unassigned      YES unset  down                  down
GigabitEthernet1/38    unassigned      YES unset  down                  down
GigabitEthernet1/39    unassigned      YES unset  down                  down
GigabitEthernet1/40    unassigned      YES unset  up                    up
GigabitEthernet1/41    unassigned      YES unset  up                    up
GigabitEthernet1/42    unassigned      YES unset  up                    up
GigabitEthernet1/43    unassigned      YES unset  up                    up
GigabitEthernet1/44    unassigned      YES unset  up                    up
GigabitEthernet1/45    unassigned      YES unset  down                  down
GigabitEthernet1/46    unassigned      YES unset  down                  down
GigabitEthernet1/47    unassigned      YES unset  down                  down
GigabitEthernet1/48    unassigned      YES unset  up                    up

The SVI 10 and 20 look fine, from the router are you able to ping both vlans?




>> Marcar como útil o contestado, si la respuesta resolvió la duda, esto ayuda a futuras consultas de otros miembros de la comunidad. <<

Yes from router everything is fine. It looks like only some ip's are not pingble. It looks like they are being blocked some where on the switch and then its dropping the connection. There is a Linux server that all clients connect to they connect to it for 30 sec and then they get dropped.

Have you disabled the firewall of windows on the computers. Also please share the configuration of the switch. 




>> Marcar como útil o contestado, si la respuesta resolvió la duda, esto ayuda a futuras consultas de otros miembros de la comunidad. <<

I just moved everything to vlan10. I dont think it was firewall as it was working before and i was able to ping from the switch via one source but not the other. 

Did you look at the host you are having issues pinging from another subnet? if it's a Linux machine you may want to ask the Linux admin to check the local IP table on that server because it may be blocking/ or doesn't know how to route traffic destined to VLAN 20 or doesn't have its default gateway configured properly.

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