Hi there, I was hoping anybody could shed some light on a problem i'm having.

I have 2 standard 2820's on the same subnet connected into our main switch in our UK branch on the 10 range, I also have the same set-up over in our Dublin office on an 11 range.

Each router has their own separate ADSL connection and static ip's.

Router1 is being used for data only and vpn tunnels with the address of 10.1.1.123 and Router2 has been set-up as a gateway 10.1.1.124 for VOIP as we have a VOIP card 10.1.1.100 in our Siemens PBX Phone System.

Router1 has an IPSEC vpn tunnel to Router1 in our Dublin office and it works fine. I also set-up the same Tunnel albeit on separate adsl lines and different IKE keys on Router2 to Router2 in Dublin, so there's 1 tunnel on 2 separate routers connecting the same subnets. 10.1.1.0 > 11.0.1.0 on Router1 and 10.1.1.0 > 11.0.1.0 also on Router2.

That tunnel also connects without any problems but as soon as it does we are having dropouts on other VPN tunnels on different subnets on Router1 even though all users are pointed to the Gateway on Router1 and bypassing Router2.

Now DHCP is disabled on both Router2's at UK and Dublin. And i'm a little stuck as to why it's causing problems when both tunnels are up and running.

Does anybody have any ideas why or point me in the right direction?

Thanks

Hi Bontempi,

One of Mikey's guides may be able to help you:

http://www.draytek.co.uk/support/vpn_setup.html

It's a little confusing reading your setup as you seem to have described two routers as "router 1" and two routers as "Router 2" - unique names would help... however, one thing you may want to look at is every subnet should have a unique address range. If you have two LANs on the same subnet then the routers won't know which subnet you want to route traffic to and hence the drop-outs.
ie on one LAN you could use 192.168.1.x
another LAN could be 192.168.2.x
But you couldn't have two LANs joined together (even through a third router) on 192.168.1.x

If you already know this then apologies but good luck!
Dudley

dudleyrees wrote: Hi Bontempi,

One of Mikey's guides may be able to help you:

http://www.draytek.co.uk/support/vpn_setup.html

It's a little confusing reading your setup as you seem to have described two routers as "router 1" and two routers as "Router 2" - unique names would help... however, one thing you may want to look at is every subnet should have a unique address range. If you have two LANs on the same subnet then the routers won't know which subnet you want to route traffic to and hence the drop-outs.
ie on one LAN you could use 192.168.1.x
another LAN could be 192.168.2.x
But you couldn't have two LANs joined together (even through a third router) on 192.168.1.x

If you already know this then apologies but good luck!
Dudley

It's ok i've sorted it out myself now, I just added some static routes on the voip router and it's perfect now.

I had only 2 routers at each site but on the same subnet of that site, one for voip only and one for just internet access and VPN's. The other offices are on their own subnet.

Thanks for the reply anyway.