08-22-2012 04:42 AM - edited 03-04-2019 05:20 PM
Hi all,
My ping works using extended vlans but not when I ping from the switch (ip 192.168.77.129)
3750#ping
Protocol [ip]:
Target IP address: 192.168.2.16
Repeat count [5]:
Datagram size [100]:
Timeout in seconds [2]:
Extended commands [n]: y
Source address or interface: vlan 888
Type of service [0]:
Set DF bit in IP header? [no]:
Validate reply data? [no]:
Data pattern [0xABCD]:
Loose, Strict, Record, Timestamp, Verbose[none]:
Sweep range of sizes [n]:
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.2.16, timeout is 2 seconds:
Packet sent with a source address of 192.168.81.1
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/3/8 ms
Now clearly the routing to and from source to destination device is correct for this ping to work from the switch so why not for 192.168.77.129? Please advise.
Solved! Go to Solution.
08-22-2012 05:09 AM
Hi Zahan,
to verify connectivity you should use:
ping 192.168.2.16 source vlan 888
and the same test with other IP addresses. I would say you should understand with which source IP the ICMP is encapsulated and checking if this IP is properly routed. In this case, when in your extended ping you specify vlan 888 the source address will be the ip address you stated in
int vlan 888
ip address 192.168.81.1 255.255.255.0
If you understand which ip address the switch use as source ip address when you do NOT specify anithing (like vlan 888) you can easily find out your issue
Take Care
Alessio
08-22-2012 05:09 AM
Hi Zahan,
to verify connectivity you should use:
ping 192.168.2.16 source vlan 888
and the same test with other IP addresses. I would say you should understand with which source IP the ICMP is encapsulated and checking if this IP is properly routed. In this case, when in your extended ping you specify vlan 888 the source address will be the ip address you stated in
int vlan 888
ip address 192.168.81.1 255.255.255.0
If you understand which ip address the switch use as source ip address when you do NOT specify anithing (like vlan 888) you can easily find out your issue
Take Care
Alessio
08-22-2012 05:24 AM
Thanks for your response.
Your right, if I specify the source address as 192.168.77.129 ping also works. so it appears that this address was not being used to ping by default. is there anyway to know which IP address the switch assumes when pinging?
thanks for your assist.
08-22-2012 05:37 AM
Difficult question
I would issue
show cdp nei det
from a cisco device directly connected!!!
Take Care
Alessio
08-22-2012 06:27 AM
Hi,
sh ip route x.x.x.x and recursion will tell you which address is used if there ain't no PBR overriding the routing behaviour.
Regards.
Alain
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