How can I get my network set up the way I want?

[Fryguy]

I have a gateway/modem that does NAT routing. Along with the gateway, which is assigned an IP, I also have 5 static IPs. The problem is, I assign static IPs to a couple of key computers on the network, and NAT the rest (mostly my wireless connections through a wireless switch used as an access point only, no connection to the wan port, and dhcp turned off). Computers with static IPs can talk to each other, but computers that get an IP from dhcp can't.

How can I fix this, short of using something like hamachi? It seems like I should be able to do this routing in hardware easily, but I can't figure it out.

Here is a pic of my current setup:

http://fryguy.nevercontent.com/mycurrentnetwork.jpg

[goldtoes]

Ok. NAT means Network Address Translation and really what it does is takes your internal IPs on your network and makes them work on the internet (so it basically goes out to the internet using your one assigned IP from your ISP).

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dhcp turned off). Computers with static IPs can talk to each other, but computers that get an IP from dhcp can't.

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ok, you say dhcp is turned off...so how can addresses be assigned by dhcp?

i would use static IP's for your certain computers that you want, and use DHCP for the rest that you don't care about.

to ensure that they can talk to each other, you need to make sure their ip's match and subnet masks match.

so say it's a Linksys router, you would want your static IP's to be:
IP: 192.168.1.101 Subnet Mask: 255.255.255.0
IP: 192.168.1.102 Subnet Mask: 255.255.255.0
IP: 192.168.1.103 Subnet Mask: 255.255.255.0
IP: 192.168.1.104 Subnet Mask: 255.255.255.0
IP: 192.168.1.105 Subnet Mask: 255.255.255.0

And you want to enable DHCP and have it start assigning addresses at say, 192.168.1.106, since the others are reserved for your statics.

Hope this made sence, and if you need more help post again.

[Fryguy]

yah I think you totally misread my post. I got things working.

I turned off dhcp on the wifi router, and had it act as a switch only (layer2). This way the gateway handled all IP allocation.

But because IPs behind the NAT are behind a NAT, the NAT drops broadcast packets, so things like finding windows computernames doesn't work. Just need to set up a local DNS server and I'll be set, for now I'm just using IPs, which are all 1-hops.

[goldtoes]

ah, sorry for misunderstanding. is it possible to use the ethernet ports on the back of the wifi router instead? would be alot easier than having to mess with DNS.

[Fryguy]

Well the wifi router is just being used as a switch/access point now, so those ports have the exact same purpose as the ones on the gateway.

If I connect the router as a router, then I lose the ability to give wireless users static IPs.

[goldtoes]

i don't understand why you would not be able to give the wireless users static IP's. i have a linksys wireless router and i can enable dhcp, but i have the option to change the starting address for the assisnged addresses.

so i use my static ips first, so say .1, .2, .3 and then start dhcp assigning at .4

this should be able to be done within the router, unless you have a cheap brand or maybe an older router?

[Fryguy]

Statics as in real statics, not internal IPs.

[goldtoes]

so when you say they "can't see each other" you're specifically talking about hostnames, but they can reach each other via IP.

then i guess DNS is the only problem. but it may be easier just to go add entries into your Hosts file instead of setting up an internal DNS server.

[Shroomy]

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Statics as in real statics, not internal IPs.

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Oh .. much different problem.
The issue is that your DNS server has your static IP's but not your NAT ip's the only way I can think of to have things work like you want is to set up a domain.

[Shroomy]

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then i guess DNS is the only problem. but it may be easier just to go add entries into your Hosts file instead of setting up an internal DNS server.

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the host file is a good idea, but I dont think it will work.
The problem is that the static IP's are listed in his ISP's DNS server so the the machines with the NAT internal IP's can see the static machines, but the static machines can not see the NAT ones.

The host file wont work because the NAT machines IP's will change sometimes.

and all the dns lookups are happening not at the router, but past the router at the ISP's dns servers.


Thinking about it a bit, the easiest thing would be if the wifi router can do ip forwarding, and just plug all the PC's into the wifi router instead of the cablemodem/router.

So all yor static ips would have an internal and external IP. That way all the machines can talk to each other.