Clear up some networking questions

[imported_Septimus]

Hi there,

I'm curious about how networks talk to each other insofar as certain devices can be considered to be on one network versus another when separated by gateways/routers/other devices. I'll use my home network as an example.

I have a desktop PC and server that have direct LAN links to a 5-port switch (provided by my ISP). It's a static IP business account (5 ports, 5 addresses).

I have a wireless router in gateway mode (Buffalo WHR-GP-W54) plugged into the third port on the switch. It handles all the other devices in the house - several laptops, a PS3, and so on. All the devices connecting to the Buffalo router get your standard 192.168.x.x NAT addresses.

The two groups of computers (wired and wireless) are effectively on different networks, even though the wireless router goes through the wired network and has one of the static IPs as its WAN address. Whatever I'm trying to do, whether it's set up a Win7 homegroup, connect via LAN for games -- they may as well be on totally different networks. They never 'see' each other. Presumably this is how it ought to be, given how I've set it up.

My question is: how else could I have set it up? If I put the Buffalo wireless transmitter in 'router' rather than 'Gateway' mode, then could it dole out the remaining 3 IP addresses from the switch to wireless clients (with other wireless clients being up a creek?)? In router mode, does the WiFi transmitter still need/get its own IP address? Put another wa, is there some other means of constituting this network such that wired & wireless will effectively be on the 'same' network, whereupon I could choose which devices get one of my 5 IPs and use NAT for the rest?

I think I'm just not very clear on how routers work versus gateways. I get the 'router is an elevator and gateway is the elevator door' analogy. I'm just not certain of when I need one versus the other.

Thanks very much!
S

 

[skyking]

In order to get the most control of your network, the most security, continue to use your router as a router. Plug other devices into it.

All the devices connecting to the Buffalo router get your standard 192.168.x.x NAT addresses.

This indicates you are using it a router now. Otherwise it would be handing out WAN addresses like your other computers have.

 

[RadiclDreamer]

I am not understanding your question entirely, so let me go over a couple things that may help you out.

A router routes packets between networks.

For example you have a 192.168.1.0/24 (255.255.255.0) network, this is a class c and the "network address" is the 192.168.1.0 and the broadcast is 192.168.1.255 so you are left if 253 usable addresses. If this network wants to speak to the 192.168.2.0 network, there will need to be a router in the middle to route between the networks.

The same goes if you are on a 192.168.1.0/27 (255.255.255.224) network, that mask means there are 32 addresses in the subnet (remembering to take out the first for network number and the last for broadcast) you are left with 30 usable IP addresses. So a host running 192.168.1.1/27 couldn't speak to 192.168.1.34/27 without a router in the mix.

It seems to me, and maybe I'm just confused, you are trying to connect the isp network ip addresses and your internal network. Is this correct? Does my terrible explanation of routing make sense? Do you see the issue with the routing between networks?

 

[imported_Septimus]

My ideal scenario is one in which I can assign my own internal IPs to whatever devices I please, and then route all 5 external IPs from my ISP to whichever devices on my internal network that I please. Right now I just have parallel networks - three desktops/servers plugged into the ISP switch, each getting one of the five available external IPs, and then my wireless router plugged into the same switch, set to 'gateway' mode, which gets a 4th external IP and doles out internal IPs via DHCP to its clients (bog-standard WiFi router behavior).

Is it possible for me to take some of my desktops from the switch, plug them into some of the LAN ports on the wireless router, but still route the external IPs to those specific machines?

It seems to me that what I'd have to do is set things up so that the WiFi router hands out static 192.168.1.x addresses to my desktops and then set up a static routing table to route those addresses to the external IPs. Is it a common thing (or even possible) to tell your Wifi router that you want it to assign static IPs to clients X, Y, and Z, but auto-assign any IP from a different range to all remaining clients?

Thank you for your patience as I figure out how to articulate my question.

 

[RadiclDreamer]

It sounds to me like what you are needing to do is have a router that supports NAT (network address translation or isp>internal address translation)

So you would say

ISP 1.2.3.4 Translates > 192.168.1.2
ISP 1.2.3.5 Translates > 192.168.1.3

etc etc

What router do you have?

 

[imported_Septimus]

The 5-port device the ISP gave me a 'Cisco 800.' I don't have any sort of password for it and I don't know if I can tamper with it.

The buffalo WiFi transmitter I'm using is a WHR-GP-W54.

 

[JackMDS]

The Cisco 800 is a Wireless Router if you use it you do not need the Buffalo.

As for 5 ISP's IPs.

Years ago before Router proliferation, ISPs use to give few IPs.

Then Router started to appear on consumer level, and for a while there were many posts like yours.

It took time to convince people that with a Router the extra External IP are useless and they should let go.

In any case there are Multi WAN Routers that can be connected to few external sources and go to one Network.

Whether you can do it with your ISP and there is an advantage to it, I do not know it depends on what the ISP is providing and what you expect to gain from it.

http://www.google.com/products/cata...ct=result&resnum=3&ved=0CBoQ8wIwAg#ps-sellers

Combining two Internet Connections - http://www.ezlan.net/loadbalance.html

.

 

[imported_Septimus]

Well, let me explain a little more what I'm trying to do. I don't really care how it's done.

I run a couple servers that are development testbeds for my small company. My link here at home is a 100 megabit cable link through Cablevision in NYC. It is of use to me to have static IPs assigned to those servers - I don't have a problem with services like DynDNS but I'd prefer to avoid them for this setup.

I don't care if I have separate machines with separate external IPs (as I have now) or if I can get a router that will take all of the static IPs for itself, hand out private ones to the machines, and then simply route accordingly. What I do know in this case is that I'm stuck with the Cisco 800 5-port that the ISP gave me (though I could try hooking another router directly to the cable modem to see if it'll still give me all 5, though I'd be surprised).

There aren't two internet connections at work and I am aware of the products you mention, but I think the only reason I have two separate networks right now is because of my own ignorance....

 

[skyking]

Nearly everything you could want to do with multiple WAN IPs can be done with a single WAN IP and alternate ports. I'd go that route.
What protocols do you want to access from the WAN on these boxes?

 

[imported_Septimus]

HTTP, FTP, remote desktop. That's it.

 

[skyking]

you can use alternate ports for RDP, there is an article at MS about that. the rest is easy as well.

 

[imported_Septimus]

I know I can use alternate ports and do everything that way. I've done that before, a while back. That doesn't really clear up my understanding, even if it is a practical solution.

Is it not possible to have device A, in this case a Cisco 800 router, doling out 5 external IP addresses, of which one is device B, in this case a Buffalo wireless router & access point, which hands out private, NAT'd IPs but which could, if desired, route one or all 5 external IPs available from the Cisco router? Or is the Cisco router the fly in the ointment here?

 

[spidey07]

The cisco router could do anything and everything you're asking. That's the purpose of NAT. If this is a managed router you'll need to call the ISP and have them setup the NAT the way you want it. Otherwise just do it yourself.

You're trying to make this a LOT harder than it needs to be. Use the bufflo router as an AP only and keep everything a single network like 192.168.1.0. Use DHCP reservations to provide IP addresses to the hosts you want to have the same address, then just map the external IPs to the internal ones.

If this is a business service with a provider router they will be more than happy to set this up for you on the 800. If not you can do password recovery on the router to change it.

 

[JackMDS]

100Mb/sec. has to be business level.

If cablevision do not have tech. support personal that know how to do it, and you can not figure it out from what was discussed until Now. You are probably better of finding an independent consultant that will do it for you.

At a certain level of tech. needs a free Internet forum is not the solution.

As for the Buffalo if there is a NAT, and DHCP on the Network, it should be configured like this.

Using a Wireless Router as a switch with an Access Point - http://www.ezlan.net/router_AP.html


.

 

[imported_Septimus]

Thanks for the site. I think that has what I need (and Cablevision has the rest).

While my account is a business account, btw, the 100 megabit offering is not exclusive to business accounts - it's new as of about five or six months ago in the NYC market (and maybe Long Island as well). $99/mo for 100 megabits down, 15 up.

 

[JackMDS]

it's new as of about five or six months ago in the NYC market (and maybe Long Island as well). $99/mo for 100 megabits down, 15 up.

Thanks for the info, being in the NYC/Long Island Market it is good to know.

.

 

[MarkXIX]

Agree with spidey07 on this. The right hardware and NAT configuration, along with several networks, VLANs, and routers (virtual or real) can do what you want.

For example, you might setup a workstation VLAN that NATs three internal hosts to three ISP external IP addresses. Then, setup a server VLAN and router instance that NATs all of your servers to a single public IP address in a DMZ type arrangement where multiple servers appear behind a single public IP, but run on different ports.

Many ways to do it, just takes some planning, the right hardware, and the right configuration.

 

[imported_Septimus]

Do VLANs require dedicated hardware or is it possible to set one up with software (I assume that's what you meant via 'virtual'?)