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Help needed with TG585 and LAN IP setup

TMBS
Newbie
Posts: 6
Registered: 12-07-2010

Help needed with TG585 and LAN IP setup

Hi people, I'm looking for some advanced help with this router we recently aquired from Plus.net.
We have a static IP address which, when connected, the router picks up from the internet.  Due to the way our internal network is set up through a hardware firewall we also need this IP address to be set up on the LAN side of the router.
The problem being is that we cannot get both the WAN and LAN to have this IP address simultaneously.  Our old Solwise router let us do this no problem.
Is there any way, through CLI, to be able to pass the IP address from the WAN through to the LAN side?
Any help is much appreciated.
TMBS
13 REPLIES
Community Veteran
Posts: 2,106
Registered: 06-02-2008

Re: Help needed with TG585 and LAN IP setup

I'm not sure how your Solwise router did this, I'm not sure if it's possible with our Thomson routers. I think there are two solutions here:
1. Use your Solwise router, just re-program it with your Plusnet username and password.
2. Request a block of four IP addresses, to use one for the router and one for the firewall. This is likely to require some re-configuring of your internal network but would be the preferable solution.
Community Veteran
Posts: 4,783
Thanks: 106
Fixes: 20
Registered: 14-07-2009

Re: Help needed with TG585 and LAN IP setup

As far as my LAN is concerned, the address of my router is 192.168.0.1 and the rest of my LAN can have addresses up to 192.168.0.255.  As far as my WAN is concerned the address of my router is completely different (and dynamically assigned by Plusnet in my case).  I think  I can make the LAN address of my router to whatever I like so I could  make it the same as my WAN IP address, or almost the same so any other computer in my network could be assigned that IP address.  The downside would be that my LAN would occupy nearby IP addresses so presumably I would not be able to access those Internet IP addresses - but that wouldn't be the end of the world.  I have a Netgear router but you must be able to do the same with a Thomson router, surely?  The only downside would be to render an infinitesimal portion of the wider internet inaccessible.       
Community Veteran
Posts: 4,783
Thanks: 106
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Registered: 14-07-2009

Re: Help needed with TG585 and LAN IP setup

If I'm right with my previous post, perhaps TMBS just needs to see this one http://community.plus.net/forum/index.php/topic,87287.0.html on how to change the LAN IP settings?
TMBS
Newbie
Posts: 6
Registered: 12-07-2010

Re: Help needed with TG585 and LAN IP setup

Thanks for the replies guys, you've given me some ideas to look at but I think I need to clarify a few things as well.
The Solwise router is one Plus.net supplied to us about seven years ago and we have decided to replace it with a new one (the TG585) as we are having frequent connection problems to the internet so are trying to find the cause.  Calls to Plus.net when this is happening show no problems with the connection coming into the building so it must be something internal to our network.
We already have multiple static IP addresses set up (router, firewall, mail server etc), it's just that the firewall looks for a connection to the router with the IP address that is assigned to it on the WAN side.  If we disconnect the router from the internet and give the IP address to the LAN side the firewall can see it OK.
I think we need to check the firewall settings to see if we can alter it to look for a different IP address for the router to avoid the conflict.
Regards,
TMBS
Community Veteran
Posts: 4,783
Thanks: 106
Fixes: 20
Registered: 14-07-2009

Re: Help needed with TG585 and LAN IP setup

Certain IP address ranges are reserved for private (i.e. local) networks.  These are:
192.168.0.1 to 192.168.255.255
172.16.0.0 to 172.32.255.255
10.0.0.0 to 10.255.255.255
It's best to set up your LAN to conform to this.
Community Veteran
Posts: 2,106
Registered: 06-02-2008

Re: Help needed with TG585 and LAN IP setup

Do you even need to use the firewall, considering the router acts as one?
TMBS
Newbie
Posts: 6
Registered: 12-07-2010

Re: Help needed with TG585 and LAN IP setup

This is a setup for a business, so we have a solution in place that consists of a hardware firewall as well as things like website filtering.  It was all installed by a third party so we're trying not to change too much that they set up for us in the first place.
Community Veteran
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Registered: 14-07-2009

Re: Help needed with TG585 and LAN IP setup

Quote from: TMBS
we're trying not to change too much that they set up for us in the first place.

I may be misunderstanding but it sounds as if it was set up badly.  Are your (fixed) LAN network addresses within the ranges I quoted?
Edit:  By which I mean do they begin 192.168. or 10. or  172.x where x lies between 16 and 32.
TMBS
Newbie
Posts: 6
Registered: 12-07-2010

Re: Help needed with TG585 and LAN IP setup

The internal network of the business was set up by ourselves (before I worked here) long before we had internet connectivity, and the IP address range isn't in the ones you specify.
Then the third party came along and put in the whole firewall / email & website filtering solution in place with the old Solwise router when we signed up to Plus.net.  This has worked OK for years up until recently when we started getting timeouts and slow connectivity to the internet, hence replacing the router to see if that solves the problem.
All this seems to be is a connection problem between the firewall and the router.
MrC
Grafter
Posts: 523
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Registered: 17-07-2008

Re: Help needed with TG585 and LAN IP setup

Quote from: ReedRichards
I may be misunderstanding but it sounds as if it was set up badly.

Bit hard to say that without knowing the full details of the existing network, or what the functional and security requirements for the original design were.
TBH as it sounds like there's a real live business hanging off this DSL connection then perhaps the easiest and less risky thing might be to get a different router/modem that will run with the same public WAN and LAN addresses. ISTR that Zyxels will do this out of the box, and perhaps Netgears as well although I'm not so sure there. It is likely that the TG585 can be made to do this (after all the WAN ip address isn't really that important in PPP and IP routing terms) but it means fiddling around in the CLI and then remembering how it was done so that it can be recreated or restored later.
Another less attractive option might be to see whether the existing firewall can have a DSL modem (internal PCI or external ethernet) added and remove the need for a separate DSL modem/router completely. Whether that's possible depends on the make/model/type of firewall.
Community Veteran
Posts: 6,366
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Registered: 30-07-2007

Re: Help needed with TG585 and LAN IP setup

As MrC says , its a fairly normal way to set up for a business when there is a 'proper' h/w firewall. Its exactly the way our office is set up, the block of 8 static Public IP's are routed to the firewall. In this situation you really need either just an ADSL modem or a router which can be set to 'bridge' mode ( effectively just a modem! ). I suspect your old solwise allowed bridge mode whereas the TG585v7 doesn't easily allow it. I've seen a few posts on the Be & ADSL24 forums which seem to indicate that it CAN be done with the TG585 but its not easy. You probably need to do a bit of googling for TG585 and bridge mode and then start experimenting....
TMBS
Newbie
Posts: 6
Registered: 12-07-2010

Re: Help needed with TG585 and LAN IP setup

Turns out we had an EOL notice for our firewall this week so we will be looking at getting it replaced sometime.  We have some other options to look at regarding the replacement so, hopefully, can get something in place and configured differently to work with the router properly.
In the meantime I will carry on trying to get this to work just for the 'fun' of it and the learning experience.
Thank you to all who replied.
TMBS
Community Veteran
Posts: 2,106
Registered: 06-02-2008

Re: Help needed with TG585 and LAN IP setup

Please let us know if you do manage to get it working as I'm sure there are others who would like to setup something similar.