VLAN Issue


#1

Hi Everyone!

I have 5 VLANs configured on my 1350, all of which where working just fine until two days ago.

VLAN 10 is configured as 192.168.1.0/24 with the gateway as 192.168.1.250, one of our partners connected to the Peplink via a PPTP session and their LAN range conflicted with VLAN 10.

Since then, machines on VLAN 10 cannot get to the outside world, but can ping other clients on the same VLAN, I also cannot ping the gateway address.

All other VLANs are operating normally

The problem seems to lie within the peplink, is there anything I can check / do to get things working again?

As an aside, if I change the VLAN IP range to say 192.168.10.0/24 it works as normal, just not with the 192.168.1.0/24 range that worked previously.

Thanks,

Dave.


#2

The PPTP user should have gotten an IP address from the default LAN segment and it should not conflict with the VLAN’s.

Sounds like you have an IP conflict with the 192.168.1.0/24 segment on your local network.


#3

Thanks Tim!

If they connected via an IPSEC VPN would you expect the same behaviour?

If there was a conflict on the 192.168.1.0/24 segment should I expect to still be able to ping all other clients on the network and its only impacting the Gateway?

Sorry for any confusion, this has me stumped!

Dave.


#4

IPSEC is a site-to-site VPN and it would definitely cause an IP conflict if one of the remote networks is identical to one of yours. If you are using IPSEC please check your profiles and make sure there are no conflicting networks.


#5

That’s what I thought thanks!

The VPN profile no longer exists, but the VLAN still can’t ping its Gateway.

Perhaps the problem lies on my L3 switch, unless I need to reboot the Peplink or anything…

Dave


#6

The ARP tables need to be cleared so a reboot of your switch and/or Peplink will do the trick.


#7

Is there a CLI command for this?


#8

No, if you just reboot your switch and router you should be all set.