Reading VLANs from the SEA Adapter
4 comments
Comment from: steve [Member]
Update on the tcpdump command.
Some switches do not return much data with the vlan and ether dst 01:00:0c:cc:cc:cd settings. I have found the following tcpdump command to be more reliable.
# tcpdump -i en26 -xx ether multicast
Comment from: patrice [Member]
There is also a possibility to see the active VLANs on the VIOS based on entstat command.
entstat command is very helpful for any network configuration.
As an example, ent7 is one SEA :
# lsdev -Cc adapter | grep -i ent7
ent7 Available Shared Ethernet Adapter
# entstat -d ent7 | grep -i vlan
VLAN Ids :
Packets filtered(VlanId): 0
Packets filtered(VlanId): 0
Number of Receive VLAN Mismatch Errors: 0
VLAN ACL Status: Disabled
Invalid VLAN ID Packets: 0
Port VLAN ID: 998
VLAN Tag IDs: 125 18 328 418 760
Management VLAN: Disabled
Comment from: steve [Member]
The tcpdump command is actually looking at the VLANs that are being bridged to the VIOS from the switch.
This can be useful when trying to diagnose VLAN related issues and you need to confirm the switch is actually sending the VLANs to the VIOS.
Whereas, the entstat command is only showing you what you have configured on the VIOS, not what the switch is sending.
Thanks and regards, Steve.
Comment from: Gery [Visitor]
I use this one since the perl part not worked for me:
Example:
tcpdump -c 100 -e -i en66 'ether[12:2] = 0x8100' -w vlantest.pcap && tcpdump -v -n -e -r vlantest.pcap | awk -F "vlan" '{ print $2 }' | awk -F "," '{ print $1 }' | sort -nr | uniq -c
^cisco6k
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