In reply to a post by john2007:

I felt that the OP raised a number of topics, and that they might be better addressed individually.

Nothing to do with me not knowing the answer to most of the questions.

I wasn't inferring that you don't know the answers. In fact I'm absolutely certain you know far more than me on this subject .

I just thought that although the article you link to might have been sufficient, and I admit to looking what it was and thinking, perhaps erroneously, that it looked a bit formidable.

You could be right that was the place to start. I thought a basic explanation, as I posted, might be easier for him first. At some point I also advised him to read your link as well, but seem to have lost that bit during re-arranging things . Sorry.

In reply to a post by john2007:

Your router will have one of the public/static/routeable IP addresses assigned to you. Your router will assign your laptop a local/non-routeable IP address, e.g. 192.168.0.5.

Ahhhh!

Now I get it ! That's one of the reasons less than 8 of the block are available for internal assignment, one of them works just like a normal single IP address?

Are you sure because it says nowhere about local IP addresses?

Just says about an overall IP address it should use.

Posted these for reference by the way:

http://i53.tinypic.com/k3of1g.png
http://i54.tinypic.com/4ihglz.png

Thanks again guys, great help as usual

It really depends on the router. In my experience on the majority of consumer grade DSL routers having devices on a routed public IP range on the LAN side removes them from the router's firewall control - so yes they may need additional protection. Of course this depends on what ports the device in question is listening on... for example some SIP/VOIP phones have web and telnet interfaces to configure them - probably wouldn't want that publically accessible even with a secure password.

As said I'm not familiar with Netgear routers so I'm not giving specific advice, just warning of potential risks. I know on Speedtouchs (now Technicolor) routers the firewall rules can be hand crafted to protect public routeable IPs on the LAN.

Damn, we need another smiley. When I said I didn't know the answers I was being truthful but used a smiley to spare my feelings!

So... presuming the devices you have on your LAN using public IPs are permanent... it will probably be best to:

a. assign public IPs to the permanent devices statically (by configuration on the devices in question)
b. configure your Netgear to route this subnet to your LAN (usually not hard to do on most DSL kit but I don't know Netgear so can't help)
c. have DHCP and NAT running on the Netgear to assign private IPs in the 192.168.x.x range to more transient devices

Some consumer grade DSL routers will fall over trying to do this kind of complexity if they also run a SPI (Stateful Packet Inspection) firewall. So if you have weird problems try disabling any SPI options during troubleshooting.

edit - typo

Edited by deleted (Fri 15-Apr-11 00:55:58)

Yes, I think so.

The OP has been given a network.

.0 is the network address
.1 is the router address
.2-6 are his usable public addresses
.7 is the network broadcast address

In reply to a post by GeeTee:

Some consumer grade DSL routers will fall over trying to do this kind of complexity if they also run a SPI (Stateful Packet Inspection) firewall. So if you have weird problems try disabling any SPI options during troubleshooting.

Or get a decent router

That or configure your LAN side devices to only listen on relevant, suitably robust ports on public IPs. May not be possible on consumer grade kit of course.

I find it a little poor that consumer grade DSL routers are being shipped that can't cope with this function. But I guess if you are serving 1mill+ customers every few pennies saved on hardware adds up - 99.99% of customers won't encounter the problem.

Kinda' catching a grip of what you guys mean now.

So if all statics run out, it'll go back to the master IP...

Can you check this out and see what I should do here? Does my router have the option? (Sorry, mentioned I had a netgear... mixed it up. Have a linksys wag354g).

Jack