How can I find out if there's a router?

[sonya2525]

Hi,

I work at a school which has a small network. It has the following servers:

1. Domain Control - DNS server
2. Domain Control - DHCP server
3. ISA (proxy) ( I don't know what ISA stands for...)
4. Antivirus Server

There is another box which all these are connected, but I think it's a switch. And there's a another box in the computer lab which all the computers are connected to; I think that is also a switch.

So I think we have around 30 computers, and we use switches.

Is there anyway I can see if we're using any routers? I would appreciate if someone could help me out.

Thank you.
Sonya

[jbennet]

switches are gererally dumb, they simply switch

whereas routers are always smart (web interface normally) and can well, route e.g port forwarding

[OlyComputers]

The easiest way is to just examine the network topography (what everything is plugged into) and see if you have a router. I doubt you do since the main practical difference between a router and a switch is DHCP functionality. If you have a DHCP server and a switch it should do the same thing as the routers.

[jbennet]

no, the main function of a router is to route between two subnets and direct traffic based on port

[sonya2525]

How can I find out if it's a router or a switch? Is there anyway I can tell by just looking at them??

[jbennet]

no.

[sonya2525]

Oh , I see. I was wondering if it would be considered unprofessional if I called up the company who set up our network and ask them for the network diagrams? I mean, it's a very small network, like I explained above. So do you think they even might have any diagrams??

[Zoraid]

Hay sonia you can find it by seeing the interfaces if it has many Rj45 ports it means it is a Switch and if its has few ports liek Aux, Console EThernet and SErial port on its back it means its a router.

Well second thing is ISA Stands for Internet and Security Accelration SErver

Zoraid.

[jbennet]

um no thats rubbish

[Stylish]

Do you have physical access to these hardware pieces? If so, grab the company and any model numbers you can find. Look them up online or call the appropriate companies.

Switches and routers both have Console, AUX, Serial, RJ45, etc [physical] ports. Some even have Fiber, piggy-back/daisy-chain and so on.

There is a router involved if your traffic is going outside your Local Area Network (LAN). If all you can access are the 30 machines in your room, then a router may not exist. (it still COULD exist) If you can utilize an outside resource, such as Google, then a Router is sitting somewhere.

A switch operates at Layer 2 (MAC Address), while a Router performs its operations based upon Layer 3 (IP Address).

If all machines have two network connections, things can be a tad more complex.

Good luck!

Oh, and asking the company which set-up the environment is definitely an avenue I would consider.

[OlyComputers]

DHCP IS what translates trafic between one network to another, and what allows two unrelated networks to interface via WAN.

Yes you can establish if you have a router or switch just by looking at the devices. They WILL have model numbers you can look up on google, if not an actual reference to what the device is (WRT350N Wireless router: It's a residential example but some hardware does specify purpose that clearly.)

You can definitely call the company that set up the router. I keep records of all the hardware I install fora client, and usually remember what they have (but I have a freakish memory and a small customer base). If the sold and installed the hardware they'll know exactly what you have, if they just installed it they'll probably have an idea. It can't hurt to ask.

I COMPLETELY LOST TRACK OF THIS POST. Somehow all the notifications got spammed, so I'm sorry if I'm too late to be of any help.

[jbennet]

DHCP IS a) what translates trafic between one network to another, and b) what allows two unrelated networks to interface via WAN.

No. Thats total crap. A) is called NAT and b) is called a gateway

[OlyComputers]

Seriously, DHCP is a component (usually the primary component) of NAT. NAT is a general term describing the translation between a WAN IP and Local IP in IPV4 (not needed in IPV6). DHCP assigns IP address to local machines providing the IP addresses involved in the translation.

A Gateway is any device that connect your LAN to a WAN. Gateways are usually a router (not always) but always something that Handles NAT. Again... NAT needs DHCP to operate unless there is another protocol, that I don't know about, that allows a NAT device to direct packets from WAN to the proper point on your LAN.

Back something up for !@#$ sake. If we're all wrong tell us what protocol we think we're talking about, if I'm misinformed about the topic I'm more than happy to be corrected but "No", "rubbish" and "crap" aren't corrections and certainly not appropriate posts for a moderator.

[jbennet]

A Gateway is any device that connect your LAN to a WAN. Gateways are usually a router (not always) but always something that Handles NAT

You can have gateways which dont do NAT, but they are essentially bridges

[OlyComputers]

I'll give you that one, I was thinking about this from a desktop perspective where whatever is shown as the "gateway" is handling NAT to the device. But your NAT device can have a gateway too (and usually does)

I'm sure Jbennet knows what I'm talking about, but for anybody who's confused imagine a group of desktops, connected to a router, connected to a DSL modem. The Router would show as the "gateway" if you did an IP config from a PC, but the modem is the gateway for the router itself.

[jbennet]

yeah in fact the modem in your example is both a gateway/bridge as it provides translation services as well as providing a physical bridge betwee media and transports of distinct types (e.g ethernet with TCP/IP and coaxial cable using something like DOCSIS)

The Router would show as the "gateway" if you did an IP config from a PC, but the modem is the gateway for the router itself

you are confusing your terms. The term "default gateway" with relation to TCP/IP and DHCP is not nececerially the same thing as the term "gateway" with relation to network maps and hardware

[OlyComputers]

That's exactly the point I was making. On a network with that layout there are acutually multiple gateways. A server that shares internet access to a network is just as much a gateway as the modem that connects the server to the WAN.

I'm not sure a standard DSL/Cable modem actually handles NAT. Since it's unable to assign local IPs, it simply allows the device connected to it to use it's IP. If you have a PC directly connected to a modem and run IPconfig it will show your public IP.

NAT has become a pretty generic term, and I'm not sure if simply directing your WAN IP to a PC counts, but I was under the impression that you had to create a new IP range to count as NAT.

[Stylish]

1) NAT (Network Address Translation) works regardless of DHCP. It TRANSLATES, not ASSIGNS.

In computer networking, network address translation (NAT) is the process of modifying network address information in datagram packet headers while in transit across a traffic routing device for the purpose of remapping a given address space into another.

Not sure I really have to go into more detail. (please note the lack of "assign", "providing addresses" or "responding to dhcp requests"). Now, NAT vs IP masquerading - those two are a bit harder to distinguish between.

2) DHCP is a dynamic configuration protocol. It has jack to do with NAT, IP forwarding, masquerading, etc, etc and so on. It does help assign DNS servers and a Gateway if one should be used.

Just so we are clear..

I'm not sure a standard DSL/Cable modem actually handles NAT. Since it's unable to assign local IPs, [...]

NAT != assigning IP addresses
DHCP != routing or anything to do with packet advancement, reversement, traversement or enjoyment.

Let's not even get started on Gateways..

[OlyComputers]

I"m still not sure which a standard modem actually does. It doesn't so much "assign" an ip address as just lends it's own IP adress to the one device connected. A serial dial-up modem certainly doesn't assign an IP adress, so I don't think that a single IP DSL modem does either (maybe you got your definitions backwards)?

Thank you very much stylish. I skimmed the wikipedia pages once I started feeling unclear on the terms. But DHCP is (also?) a protocol for assigning IP adresses, as stated on the same wikipedia page you quoted. at least in MY use, the main thing I do with DHCP is to allocate IPs.

I don't think I ever said NAT NEEDED DHCP, just that DHCP was a component (that can be bypassed by other means of assignment.) but I did misspeak in post #11 when I said DHCP translates the information, I meant that it provides destinations for the information to be directed to.

This post really has just gotten mixed up...but I think the information Sonya needs was covered, I hope you were able to sort through everything and receive an answer to your question. If we didn't tell us what you're still unsure about and we'll try to give you a more...focused answer.

[jbennet]

I'm not sure a standard DSL/Cable modem actually handles NAT. Since it's unable to assign local IPs, it simply allows the device connected to it to use it's IP. If you have a PC directly connected to a modem and run IPconfig it will show your public IP.

Wrong. My ISP-provided cable modem acts as a DHCP server and performs NAT. The machine connected to it gets assigned 192.168.1.2, the modems internal IP is 192.168.1.1

[OlyComputers]

Some, do, not all. I Know some assign a local IP adress, and some even have built in routers. That's why I said "standard", maybe I should have been more clear and said " I'm not sure if all". But several of my local Ips here just give you your WAN IP.

[Stylish]

This post really has just gotten mixed up...but I think the information Sonya needs was covered, I hope you were able to sort through everything and receive an answer to your question. If we didn't tell us what you're still unsure about and we'll try to give you a more...focused answer.

Agreed.

Good luck!

[gerryburon]

If you can connect to an outside network, or the internet, then you have a router.

A router connects different networks (different IP addresses).