2700 & DHCP

Tacitus · Dec 10, 2008, 10:19:27

Sorry for the ramble, but the story so far.

The 2-Wire arrived the other day and after some hassle I've got it up and running. So far there is only a modest improvement with the connection speed, SNR & attn are up on what was previously reported (2368/2240: 57dB attn 15dB SNR against 54dB and 11dB). These may well change a little as the 2-Wire adjusts, but suggests the 2-Wire has better noise discrimination. I really wish they did a vanilla modem which I could use with a Zywall for VPN, but unfortunately not.

To the problem. For some reason I can't get it to accept both fixed IPs and DHCP assignments on the same network. Normally I use a block of fixed LAN IPs together with with a range of DHCP set outside the fixed ones range to avoid conflicts. It's worked with every other router I've used, but for some reason not with the 2-Wire.

I know the 2-Wire will use MAC addresses to 'fix' an IP to a particular machine, but does anyone know why the system outlined above won't work? I don't really want to go round all the machines and set them to use DHCP if I can avoid it.

Rik · Dec 10, 2008, 10:44:57

It should work, Tac. I have my laser at a fixed IP address, all I did was set it at the printer.

Tacitus · Dec 10, 2008, 10:53:00

Quote from: Rik on Dec 10, 2008, 10:44:57
It should work, Tac. I have my laser at a fixed IP address, all I did was set it at the printer.

I thought it should Rik. Not a problem with my main machine which has two network sockets - I can config individually and swap the lead.

Rik · Dec 10, 2008, 10:54:52

I assume the fixed addresses are in the 2700's range, Tac?

kinmel · Dec 10, 2008, 11:27:18

The only way I can manage it is to set a wider than necessary range in DHCP and then set the fixed IPs within that range on the Address Allocation page.

The router then reserves the Fixed IP for the device name and provides dynamic IPs for any that have not been specified as fixed, the router avoids clashes.

Tacitus · Dec 10, 2008, 12:17:26

Quote from: Rik on Dec 10, 2008, 10:54:52
I assume the fixed addresses are in the 2700's range, Tac?

Yes they're just at the lower end of the range. I've put the DHCP allocations at the upper end well away from any of the fixed ones.

Quote from: kinmel on Dec 10, 2008, 11:27:18
The only way I can manage it is to set a wider than necessary range in DHCP and then set the fixed IPs within that range on the Address Allocation page.

The router then reserves the Fixed IP for the device name and provides dynamic IPs for any that have not been specified as fixed, the router avoids clashes.

I think that's the way I shall have to do it. I noticed there was this option but it means I shall have to configure each machine to use DHCP rather than the fixed allocation I've given them at present.

Whilst I'm here, is there anywhere you can find the total uptime? There are plenty of stats but not that one - at least not that I can see.

Rik · Dec 10, 2008, 12:33:28

Never seen it, Tac, only time from last reset (boot).

Sebby · Dec 10, 2008, 20:19:21

What exactly is the problem? I have my printer with a fixed IP with the computers using DHCP... What am I missing?

kinmel · Dec 10, 2008, 20:58:43

Quote from: Sebby on Dec 10, 2008, 20:19:21
What exactly is the problem? I have my printer with a fixed IP with the computers using DHCP... What am I missing?

If the IP is fixed at the PC and not at the router, it is possible that the router will have already allocated the PCs "fixed" IP dynamically to another client and the PC will not be able to connect.

If using DHCP then all IPs need to be allocated by the router. The router can reserve an IP for the sole use of a known client, which avoids the problem. Tac is trying to save the time needed to alter the PC's network adaptor's settings.

Sebby · Dec 10, 2008, 23:07:18

Right. Well I just reduced the DHCP range and set the fixed device outside of this range. Doesn't that work?

kinmel · Dec 11, 2008, 09:00:33

Some of us can't do that. How do you manage it ?

Sebby · Dec 11, 2008, 13:55:13

Exactly as I said. It just worked!

kinmel · Dec 11, 2008, 14:34:36

Quote from: Sebby on Dec 10, 2008, 23:07:18
Right. Well I just reduced the DHCP range and set the fixed device outside of this range. Doesn't that work?

Are you fixing the IP at the router or on each device itself ?

Sebby · Dec 11, 2008, 23:10:16

On the device itself.

Rik · Dec 12, 2008, 09:47:54

Same here.

kinmel · Dec 12, 2008, 09:55:34

If I set one fixed outside the DHCP range it fails to connect, I will try a spare set to factory defaults and have a play around.

Rik · Dec 12, 2008, 10:02:10

I used DNS Resolve to define the printer's IP address, Alan, which is in the normal DHCP range, but well away from the assigned addresses.

Tacitus · Dec 12, 2008, 10:26:15

OK another problem with the 2-wire.

Broadband link -> advanced settings

Whenever I try to change my DNS settings from automatic to manual, (eg to use Open DNS), click 'Save', it offers the information that my PPP username is not correct. It is and must be since I have a connection.

Any ideas?

Steve · Dec 12, 2008, 10:38:14

Tac from LesD pdf guide.

Note when this configuration data is complete do not click the Submit Settings button at the bottom of the page.
At first this is what I did and it does not work.
Instead in your browser's address bar type: javascript:document.pagepost.submit() and press enter.
This saves the correct details but bypasses the validation present in the BT firmware.

Rik · Dec 12, 2008, 10:39:02

What Steve said.

kinmel · Dec 12, 2008, 13:10:40

Quote from: Tacitus on Dec 12, 2008, 10:26:15
OK another problem with the 2-wire.

Broadband link -> advanced settings

Whenever I try to change my DNS settings from automatic to manual, (eg to use Open DNS), click 'Save', it offers the information that my PPP username is not correct. It is and must be since I have a connection.

Any ideas?

It is an undocumented feature !

You can simply ignore it, the changes you made will still take place and be remembered.

Rik · Dec 12, 2008, 13:13:07

I thought all the features were undocumented, Alan.

Tacitus · Dec 12, 2008, 14:06:10

Quote from: stevethegas on Dec 12, 2008, 10:38:14
Tac from LesD pdf guide.
.....
Instead in your browser's address bar type: javascript:document.pagepost.submit() and press enter.
This saves the correct details but bypasses the validation present in the BT firmware.

Brilliant!! Thanks Steve, Alan & LesD. I guess it always pays to RTFM.......

My main reason for wanting to specify the DNS servers is that I want to know what servers I am dealing with rather than leave it to others to decide.

Rik · Dec 12, 2008, 14:12:03

You could always try the IDNet ones, Tac.

212.69.36.3 Primary
212.69.40.3 Secondary

Tacitus · Dec 12, 2008, 14:31:48

Quote from: Rik on Dec 12, 2008, 14:12:03
You could always try the IDNet ones, Tac.
212.69.36.3 Primary
212.69.40.3 Secondary

Thanks Rik, I'll give them a go.

One of the more interesting things about the 2-Wire is the amount of info it gives you regarding the line. I have a connection at 2240 with an SNR that has not varied from 15dB. CRCs/FECs are 82/848 which I think suggests the line is not that noisy. This would be since around 7.30am today, assuming these are running totals.

So far it doesn't seem to be giving be much higher syncs than my old (AR7) router. Best sync I've seen was 2420 which isn't a lot higher than the 2336 that the old router gave at best. Stability seems much the same, although the 2-Wire might not get thrown by sudden large noise bursts compared to the old one.

We'll see.