Hi all,

My only experience in networking is with fixed IPs. I have 12 sites up and running with many computers each, all running on fixed IPs via various Draytek Vigor routers without any problems. I have VPNs connecting them all and it's all smooth sailing.

Recently I installed a Vodafone FemtoCell at one site and this insists on a DHCP assigned IP address, so I had to change the setup at that site from fixed IPs to DHCP assigned IPs.

I am a COMPLETE novice when it comes to DHCP and after reading up on things a bit I successfully got the router (2820n) up and running and all computers onsite are connecting to the internet through wireless connectivity without any problems.

HOWEVER - I cannot share anything between the machines and when I try to ping any of computers on the wireless network I get a "Reply from 192.168.1.18: Destination host unreachable". The IP address obviously changes for different machines.

I've tried to set up a Home Network Group in Win7 but cannot connect to any of the other machines. The other clients are shown in the network map but the connecting lines are only dotted. When I use the web interface on the router I can ping all connected clients successfully from the router but when doing this between the clients directly I get the above result.

As I'm really not familiar with DHCP I must have set something up incorrectly and simply cannot figure out what it is. Probably something really simple.....

Please be gentle with me!!!

Thanks
Florian

Router 192.168.1.1
Clients 192.168.1.10-192.168.1.20
Subnet 255.255.255.0
Vigor 2820n
Firmware: 3.3.2.1_232201
Win7 and Vista mixed environment
HP wireless printer

You can go back to fixed IP's if you want! If you set everything back to where it was, but enable DHCP on the router for a small range of one IP which you want the Femtocell to have and connect the Femtocell.

I am not a 2820 person but I believe you have a Bind IP to MAC menu somewhere in the set up. The next trick is to bind the Femtocell's MAC to the IP address. Again I do not have the manual but I think there is an option to convert the current IP to the MAC. This means that the DHCP server will always give out the same IP address to the Femtocell. If not you will have to manually bind the MAC to the IP. If needed you can read the MAC of the Femtocell from the ARP cache in the management diagnostics.

Once you have done that and you want to stop other people joining the network using DHCP I suggest you change the DHCP range again to something which is not in use, then create block rules for it so it cannot access anything (apart from devices in the LAN which I do not think you can block)

There is no problem with fixed IP's and bound IP's co-existing with DHCP as long as the ranges do not overlap.

Ah, didn't know that one could mix fixed and DHCP assigned IP adresses within the same network!

Some of your reply is a little over the top of my head but I'll give this a go. Vodafone do however state that ANY kind of fixed IP on the network where the femtocell is won't allow it to build it's VPN back to their servers though.

I'm not insisting on fixed IPs on that site and would be quite happy to use DHCP for everyone but just can't get the clients to see each other?

I did not know that about the FemtoCell. I've no idea what it is or how it works. If it really does not like fixed IP's at all, as long as you don't blow the 2820's limit, you can cheat and let everyone have dynamic IP's, but then use the Bind IP to MAC facility to make sure they always get the same dynamic IP. This means they are not fixed in the traditional sense, but they will always get the same IP. On older routers without a GUI for it, you could only bind 10 IP's. I don't know how many IP's the 2820 will support bound to MAC's.

The femto cell, Vodafone's 'Sure Signal' acts as your own cellular 'base station'. You connect it to your router, register your mobile phone to it and it then automatically builds a VPN through to Vodafone's servers. You get a full-bar 3g signal and your data over the phone runs at the speed of your broadband connection (well, up to 7.2mps anyway).

The unit insists on dynamic IP (even Vodafone's tech support can't confirm why) for it's VPN.

Did you resolve the issue as I have a 2820 and the same femtocell.

I can assit you in setting it up if you need me to.