Real IP to Many real IP's routing

[tparker]

Apologies for the rather elementary title!

I've switched ISP's and for the first time find myself with a connection that requires me to get my own router, which takes one real IP and splits it to another block of real IP's.

In other words, I have 64 IP's for this connection, but aside from that block, i'm given another single IP and route/mask as my uplink.

In the past, i've always either been given this equipment pre-configured, or just plugged my uplink to a switch and I configure my real IP's directly on each device.

What is this type of routing called? I need to buy a router, but obviously a household one would not cut it.

Thanks

Terence

 

[Gryz]

All routers should be able to do this. This is ordinary routing.

What you (and most other people) are used to, is called Network Address Translation (NAT). With NAT, you get 1 "public" ip-address. And you'll use a bunch of "private addresses" inside your own LAN. (Usually in the 10.0.0.0/8 range, or 192.168.0.0/16 range). With your new setup, you won't use NAT. So you can't use private addresses on your internal network.

Your setup is not very complicated. What you need to configure is probably:
1) Connect your router to the outside line.
2) Connect your PC via an ethernet cable to a LAN port on the router.
3) Turn on your PC. You'll get a private address via DHCP on your PC.
4) Connect to the router's configuration webpage.
5) Turn off NAT on the router.
6) Re-configure the ip-address of the router's internal ethernet-interface. Use an ip-addres from the block that you got from your ISP. This will cause you to lose all connectivity to your router.
7) Reboot the PC. You will get a new ip-address on your PC. (If not, hard-reset the router. Try again. But check the DHCP settings. Change the DHCP-pool to the block you got).
8) You can now connect to the router again. (But both router and your PC will use an ip-address from the official public block you received from your ISP).
9) Turn off NAT on the router.
10) Test Internet-connectivity. Maybe your router got an ip-address for its external interface via DHCP from your ISP's router. If not, configure the external interface with the IP address you got from your provider.

It's not that hard. Should take 10-30 minutes max.
The key part is turning off NAT.
I just checked my own router (a so-called Fritzbox). But to my surprise, there seems to be no option to turn off NAT. I googled a bit, and saw screenshots of how to disable NAT. But my firmware does not seem to support that option any more. Weird. So before you buy a router, make sure it is one where NAT can be disabled.

 

[tparker]

Thanks for that.

No, I wasn't on NAT before - i'm quite familiar with that. With all previous servers i've run either the ISP provided a router, or it's a direct RJ45 connection to some equipment of theirs locked up somewhere... but all I needed to configure IP and I was good to go. So never really had to do non-NAT routing myself.

Interesting that you're suggesting (in effect), that any crappy household router which supports turning off NAT should work. I will give that a go. I was thinking that, surely, something more fancy is required here?

If this is the case though it certainly makes my life easier. Thanks.

 

[imagoon]

Thanks for that.

No, I wasn't on NAT before - i'm quite familiar with that. With all previous servers i've run either the ISP provided a router, or it's a direct RJ45 connection to some equipment of theirs locked up somewhere... but all I needed to configure IP and I was good to go. So never really had to do non-NAT routing myself.

Interesting that you're suggesting (in effect), that any crappy household router which supports turning off NAT should work. I will give that a go. I was thinking that, surely, something more fancy is required here?

If this is the case though it certainly makes my life easier. Thanks.

It might be. You didn't really state your use case. If this is a business with say 2000 employees, I don't think the little at home router is going to fair to well. The fact that you have 64 IPs in what might be a asian country (from your location) means that someone dropped some decent coin on the IP block since those are pretty limited in that area of the world at the moment.

"Home routers" rarely have [good] concepts of multiple internal and external IPs.