ADSL "Embarras de Richesse", now, how to configure it?
I have just had our BT business line ADSL enabled, going for their "BT Business Total Broadband" Option 1 means we'll probably pay no more to BT in total (we had a BT business phone line anyway) and now we have a backup ADSL connection. It was scheduled to start working on 3rd March but I plugged in their supplied router today and it all burst into life. I have to say it was dead easy and the router (a 2Wire 2700HGV) and its software seem pretty good. The 'advanced' tabs in the router set up seem to give one a fair amount of control. So now to my "Embarras de Richesse" dilemma, I now have two ADSL connections, what's the best way to set it up? I have two similar ADSL routers each providing about the same bandwidth (both 448kb/s up, both around 4Mb/s down), what's the best way of using them to full advantage. There are some obvious things I have to do:- Change the address of one of the routers so they're not both 192.168.1.254 Turn off DHCP on at least one of the routers (unless I split subnets, see below) But I can arrange things various ways and I'm not at all sure which will work best.... Leave everything on one subnet (192.168.1.xxx) or split into two subnets? At the moment I can't see any really significant advantages in splitting subnets and it would be quite a lot of hassle I suspect so, unless anyone can come up with some really good reason for doing it, I don't think this is a sensible option. We have two main users, it *feels* like it would make sense to use one ADSL router as the default gateway for one user and the other ADSL router as the default for the other user. Then set up so that the 'other' router is the alternative gateway. Are there any downsides to this approach? I don't think there's any easy way to use both routers from one system (to use up all the bandwidth) is there? At least there isn't without a lot of hassle. Any advice and ideas gratefully received. -- Chris Green
On Fri, 2008-02-29 at 09:20 +0000, Chris G wrote:
the router (a 2Wire 2700HGV) and its software seem pretty good. The 'advanced' tabs in the router set up seem to give one a fair amount of control.
My main issue with those is that the firewall/port forwarding settings are initially a bit confusing as they are done by machine name not just a list of rules against ip addresses and if the Router isn't the thing on the network handing out DCHP leases then they are done by mac address or something. Also why why why when BT are shipping their routers to their customers they insist on leaving them set at a non optimal MTU for the BT adsl network (which causes issues with several vpn solutions and various other things) is beyond me.
There are some obvious things I have to do:-
Change the address of one of the routers so they're not both 192.168.1.254
Turn off DHCP on at least one of the routers (unless I split subnets, see below)
Even if you end up with them on different subnets, if they are on the same physical network you need to be turning off DHCP on one of them.
But I can arrange things various ways and I'm not at all sure which will work best....
Leave everything on one subnet (192.168.1.xxx) or split into two subnets? At the moment I can't see any really significant advantages in splitting subnets and it would be quite a lot of hassle I suspect so, unless anyone can come up with some really good reason for doing it, I don't think this is a sensible option.
We have two main users, it *feels* like it would make sense to use one ADSL router as the default gateway for one user and the other ADSL router as the default for the other user. Then set up so that the 'other' router is the alternative gateway. Are there any downsides to this approach?
Not really, an alternative is to run one router for desktop browsing and the other for things like mail services, remote access etc with of course the ability to swap one service to another if needed. You could if you wanted to be very clever probably rig up something with RIP and gateway metrics to automate the changeover and then put your external services on dynamic DNS.
I don't think there's any easy way to use both routers from one system (to use up all the bandwidth) is there? At least there isn't without a lot of hassle.
To pool the lines together and use the total bandwidth as one connection would require ISP co-operation even if the connections came from the same provider. Then from your end you have to ditch the two routers and either have a linux box with two ADSL interfaces (or two pppoe interfaces to adsl modems) or buy a lot of money's worth of Cisco with two ATM interfaces. I have done it the cisco way before and it wasn't fun to configure.
On Fri, Feb 29, 2008 at 10:02:14AM +0000, Wayne Stallwood wrote:
On Fri, 2008-02-29 at 09:20 +0000, Chris G wrote:
the router (a 2Wire 2700HGV) and its software seem pretty good. The 'advanced' tabs in the router set up seem to give one a fair amount of control.
My main issue with those is that the firewall/port forwarding settings are initially a bit confusing as they are done by machine name not just a list of rules against ip addresses and if the Router isn't the thing on the network handing out DCHP leases then they are done by mac address or something.
It actually seems very similar indeed to my Speedtouch so, even if a little odd, was fairly easy to understand.
Also why why why when BT are shipping their routers to their customers they insist on leaving them set at a non optimal MTU for the BT adsl network (which causes issues with several vpn solutions and various other things) is beyond me.
So should I change it? If so, what to?
There are some obvious things I have to do:-
Change the address of one of the routers so they're not both 192.168.1.254
Turn off DHCP on at least one of the routers (unless I split subnets, see below)
Even if you end up with them on different subnets, if they are on the same physical network you need to be turning off DHCP on one of them.
Yes, I was meaning actually physically splitting the network as well, but I don't see any point.
We have two main users, it *feels* like it would make sense to use one ADSL router as the default gateway for one user and the other ADSL router as the default for the other user. Then set up so that the 'other' router is the alternative gateway. Are there any downsides to this approach?
Not really, an alternative is to run one router for desktop browsing and the other for things like mail services, remote access etc with of course the ability to swap one service to another if needed. You could if you wanted to be very clever probably rig up something with RIP and gateway metrics to automate the changeover and then put your external services on dynamic DNS.
OK, thanks, I think I'll go with the simple approach initially.
I don't think there's any easy way to use both routers from one system (to use up all the bandwidth) is there? At least there isn't without a lot of hassle.
To pool the lines together and use the total bandwidth as one connection would require ISP co-operation even if the connections came from the same provider. Then from your end you have to ditch the two routers and either have a linux box with two ADSL interfaces (or two pppoe interfaces to adsl modems) or buy a lot of money's worth of Cisco with two ATM interfaces. I have done it the cisco way before and it wasn't fun to configure.
Yes, as I thought, not really a serious possibility. Thanks for all the comments/help. -- Chris Green
On Fri, 2008-02-29 at 10:53 +0000, Chris G wrote:
Also why why why when BT are shipping their routers to their customers they insist on leaving them set at a non optimal MTU for the BT adsl network (which causes issues with several vpn solutions and various other things) is beyond me.
So should I change it? If so, what to?
1458 would be the recommended value for your connection. What you should also do is make sure that from your end at least there is no reason for pMTU not to work (generally your end that would mean making sure ICMP can get out of your network and potentially allowing it in as well) this I think is probably the default behaviour for your router Generally speaking Path MTU should mean that a MTU setting that is too high on the PC's or your router is irrelevant, however there are a number of systems on the internet that are broken in respect to pMTU which is why occasionally you may get a problem with the default setting of 1500.
On Sat, Mar 01, 2008 at 11:14:19AM +0000, Wayne Stallwood wrote:
On Fri, 2008-02-29 at 10:53 +0000, Chris G wrote:
Also why why why when BT are shipping their routers to their customers they insist on leaving them set at a non optimal MTU for the BT adsl network (which causes issues with several vpn solutions and various other things) is beyond me.
So should I change it? If so, what to?
1458 would be the recommended value for your connection. What you should also do is make sure that from your end at least there is no reason for pMTU not to work (generally your end that would mean making sure ICMP can get out of your network and potentially allowing it in as well) this I think is probably the default behaviour for your router
Generally speaking Path MTU should mean that a MTU setting that is too high on the PC's or your router is irrelevant, however there are a number of systems on the internet that are broken in respect to pMTU which is why occasionally you may get a problem with the default setting of 1500.
OK, thanks for the helpful information. I have to say that in all my time using the internet (dating back to early Demon "tenner a month" days) I've never (knowingly) suffered from any problems caused by MTU size. -- Chris Green
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Chris G -
Wayne Stallwood