Switches, Hubs, and Modems
cancel
Showing results for 
Search instead for 
Did you mean: 

VLAN not reachable

adurotec_1
Advisor

VLAN not reachable

Some history, I was troubleshooting a NAT translation issue and discovered that the failure was due to the wrong IP being used for traffic to the GW. My hosts which have 2 NIC cards have one interface assigned to a VLAN that is service specific and one interface assigned to a "central" VLAN which will be used for admin access etc. I realized that the initial configuration on the servers had a GW IP assigned to both interfaces which was causing the NAT policy to fail (I specified one IP but the other IP was seen at the FW). So I removed the GW IP from the interfaces that were part of the central VLAN since a host can't have more then one GW.

Everything seemed ok until I tried to ping the IP addresses assigned to the interfaces that are part of the central VLAN. I can ping some of the addresses but not all of them from my laptop to which I VPN into my data center to gain access to the LAN via a vlan between the FW and my 5406zl switch.

I get the same results when I ping the hosts from the FW itself, however if I log into the 5406 switch (which is assigned an IP from the VLAN that is between the FW and the LAN) I can ping the hosts just fine. I can also ping every one of the IP addresses assigned to this central VLAN from any host that is in a different VLAN from with my LAN.

Does anyone have any idea why this is occurring? Why would some hosts in the VLAN be reachable while others are not from the FW or from a VPN tunnel to the FW. I started thinking it has something to do with MTSP but I am not sure if this is the reason and how I would prove it or rule it out.

Thanks,

David
1 REPLY
adurotec_1
Advisor

Re: VLAN not reachable

Going to try to post this a different way with new information I gather during troubleshooting