Thomson TG585 Wrong Default Gateway on DHCP

[#1]

Hi,
I've recently moved my Dad over to PlusNet (from NTL) and he's received the Thomson TG585 router from PlusNet. I tried installing this last night and have hit a problem and wonder how others have fixed this.
His LAN is configured in the 192.168.0.x range and (since he has a number of PCs and other devices) so I've changed the Thomson from it's default 192.168.1.x range to 192.168.0.x. However, the Thomson is still dishing out DHCP configurations that have the default gateway as 192.168.1.254 and there seems no option to change it. All client machines are getting  their IP address, DNS servers, etc. are correctly configured through DHCP but it is just this one element that's wrong and because it's giving out a default gateway on a different subnet it effectively means no internet connectivity for clients. Frustratingly, if I go into the Thomoson config (screen shot attached) there is no facility to amend the default gateway.
Now I've managed to get around this on his Windows machines because, even with DHCP, I can manually add a new default gateway (with correct address) with a high metric in advanced TCP/IP properties but I don't have this facility for his other devices (eg. iPhone, etc.) so I really do need a solution.
Obviously, I appreciate that if I reconfigure his LAN to be in the 192.168.1.x range that would be a work around but I don't see why I should go round and do this when the router really ought to be capable of using different ranges.
Can anyone help!
Many thanks, David.

[#2]

Hi daveyb,
If you click the 'Add' button under the DHCP pools section are you not able to specify the gateway IP in the options there? The one I'm looking at is for an older firmware version but the option is definitely there. Is it missing on yours, or does it just not update the gateway IP if you edit it?

[#3]

Thanks Matt.
Yes and I did try that last night.  You can add another DHCP pool but you can't delete the first one (presumably the default range must stay) and AFAIK you then need to exhaust the first DHCP pool (some 50 odd addresses) before it gets to the second pool with the correct default gateway.
Effectively in a home environment you never get to the second range and hence that doesn't seem to offer a solution.

[#4]

There is a way to do what you want, if you are prepared to backup, edit and reload the configuration. Just globally edit 192.168.1.  to  192.168.0.
It's what I have done with my TG585v7
Alternatively, you can make the changes using telnet, if you can find the CLI manual
Phil
[Edit]  You will need to remove the second pool as well, either through configuration or delete the entry under [ dhcs.ini ] in the .ini file [/Edit]

[#5]

You can delete the default DHCP pool as long as you delete all the active devices that are using the old IP range.
Instructions here may help.....
http://www.speedtouch.net.nz/500ChangeIPaddress_v4.3.htm

[#6]

Excellent guys - both of those sound good options. I'll give them a go tomorrow once the excitment of the BBC endless pouring over just 3 results has worn off 

[#7]

I had the same problem, solved by....
1. Set PC up with a static IP address, ie not to depend on the router's DHCP facility, browse to the router and...
Set router address to desired value, in my case for this example use 200.200.0.90
2. In Home Network> Interfaces> Local Network. Click link at bottom of page "Add IP address or DHCP pool"
Add a 2nd DHCP pool, with desired address range of eg 200.200.0.100 - 200.200.0.199 and required Gateway ie 200.200.0.90
3. THIS IS THE CRUCIAL BIT:
Go into Home Network> Devices and delete each device apart from the PC you're working on
this makes the "delete" link appear next to the first DHCP pool
4. Now in Home Network> Interfaces> Local Network>  "Add IP address or DHCP pool"
we can delete the first DHCP pool, ie the one that has the bad default gateway value of 192.168.1.254

[#8]

If anyone uses that procedure I suggest *not* using the IP address range 200.200.x.x on home networks. That address range is live on the Internet and using it could cause identity confusion.
IANA (Internet Assigned Numbers Authority) has allocated three address ranges which can safely be used for private (home) networks which are 10.0.0.0 - 10.255.255.255, 172.16.0.0 - 172.31.255.255 and 192.168.0.0 - 192.168.255.255 . However BT appear to use 172.x.x.x as temporary addresses while routing users to their ISP so I suggest avoiding that one.
Also avoid using 255 or 0 as the last octet, those have special meaning.