11-04-2011 08:53 AM - edited 03-07-2019 03:13 AM
I have a strange situation:
Host A is physical and connected to a switch port directly
Host B is virtual (VMWARE) and is on a vSwitch which is connected directly to the same switch as host A
Spanning the ports these hosts use I am finding something strange:
If some other host C,D, or F pings these I get the expected captures of seeing the source and destination hosts macs.
When looing at traffic between Host A and Host B they are using the MAC of the default gateway to communicate as if they don't think they are on the same subnet.
However I have reviewed the config of each twice
- Both have the correct subnet IP and mask
- Both have each others MAC in their arp cache
Any tips as to why this might happen? I am having intermittent connectivity issues between them, and have replaced the cabling and changed the switch ports already... They only seem to have trouble communicating with each other on occasion.
11-04-2011 09:04 AM
Hi,
are they in the same VLAN?
Regards.
Alain.
11-04-2011 09:13 AM
They should both be in the "Default" vLan however as we all know "Default" means something differnet to each vendor "no tag, 0 or 1"
There is no explicit tagging begin done in VMware and both ports are in their default mode and when doing a listing on vLan membership on the cisco switch both both appear to be members of VLAN 1 as expected.
11-04-2011 09:16 AM
Hi,
can you post sh interface switchport output for the 2 ports.
Alain.
11-04-2011 09:25 AM
show interface GigabitEthernet 0/17 switchport
Name: Gi0/17
Switchport: Enabled
Administrative Mode: dynamic auto
Operational Mode: static access
Administrative Trunking Encapsulation: negotiate
Operational Trunking Encapsulation: native
Negotiation of Trunking: On
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 1 (default)
Administrative Native VLAN tagging: enabled
Voice VLAN: none
Administrative private-vlan host-association: none
Administrative private-vlan mapping: none
Administrative private-vlan trunk native VLAN: none
Administrative private-vlan trunk Native VLAN tagging: enabled
Administrative private-vlan trunk encapsulation: dot1q
Administrative private-vlan trunk normal VLANs: none
Administrative private-vlan trunk associations: none
Administrative private-vlan trunk mappings: none
Operational private-vlan: none
Trunking VLANs Enabled: ALL
Pruning VLANs Enabled: 2-1001
Capture Mode Disabled
Capture VLANs Allowed: ALL
Protected: false
Unknown unicast blocked: disabled
Unknown multicast blocked: disabled
Appliance trust: none
show interface GigabitEthernet 0/9 switchport
Name: Gi0/9
Switchport: Enabled
Administrative Mode: dynamic auto
Operational Mode: static access
Administrative Trunking Encapsulation: negotiate
Operational Trunking Encapsulation: native
Negotiation of Trunking: On
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 1 (default)
Administrative Native VLAN tagging: enabled
Voice VLAN: none
Administrative private-vlan host-association: none
Administrative private-vlan mapping: none
Administrative private-vlan trunk native VLAN: none
Administrative private-vlan trunk Native VLAN tagging: enabled
Administrative private-vlan trunk encapsulation: dot1q
Administrative private-vlan trunk normal VLANs: none
Administrative private-vlan trunk associations: none
Administrative private-vlan trunk mappings: none
Operational private-vlan: none
Trunking VLANs Enabled: ALL
Pruning VLANs Enabled: 2-1001
Capture Mode Disabled
Capture VLANs Allowed: ALL
Protected: false
Unknown unicast blocked: disabled
Unknown multicast blocked: disabled
Appliance trust: none
11-07-2011 11:09 AM
Root cause was a static route on the windows host which had two nics in the same subnet.
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