do I need two nics?

[Milo]

I'm going to set up a small peer to peer network for a company. Just four
computers with one of them being the shared file and print server. Right now
their internet connection is provided by their office building with the
internet connection price included in their monthly rent. Each machine is
currently a standalone device and its nic is wired to the building's
cabling, solely to connect to the common DHCP server. My question is how I
can go about creating the lan but let them continue with their current
internet connection. I need a nic in each computer plus a switch so that all
machines can see each other and shared resources. Should it work that I
simply run new cables for the in office lan and leave one ethernet cable
connected to the building's internet connection? I would think that all
machines would then be able to contact the DHCP server via the local switch.
Right? I'm trying to avoid having to install a second nic in each machine.

Thanks.

 

[cphillips581]

I'm going to set up a small peer to peer network for a company. Just four
computers with one of them being the shared file and print server. Right now
their internet connection is provided by their office building with the
internet connection price included in their monthly rent. Each machine is
currently a standalone device and its nic is wired to the building's
cabling, solely to connect to the common DHCP server. My question is how I
can go about creating the lan but let them continue with their current
internet connection. I need a nic in each computer plus a switch so that all
machines can see each other and shared resources. Should it work that I
simply run new cables for the in office lan and leave one ethernet cable
connected to the building's internet connection? I would think that all
machines would then be able to contact the DHCP server via the local switch.
Right? I'm trying to avoid having to install a second nic in each machine.

Thanks.

Just buy a wired router such as the Linksys BEFSR41 or any other
similar model by other companies such as DLink, SMC etc.
Each PC is wired to the router and the incoming cable is connected to
the WAN port on the router. It also provides a basic hardware firewall
function as a bonus. The router contains an internal DHCP server of
it's own and it gives the PC's an address on the internal LAN. The
router itself uses the address obtained from your ISP's DHCP server.

HTH

 

[Milo]

what difference would there be if I disabled DHCP on the router I purchased
and simply plugged the wire from the building's router into one of the
available lan ports on my router? (I'd essentially be using it as a switch,
not as a router) And wouldn't there be a conflict in having two routers on
one lan. I understand about private ips (192.168.x.x) vs public ips.
Wouldn't the building be giving me a private ip and then my own router, the
one I'd purchase according to your scenario, would also give users an
address in the private, non-routable range?

The building's incoming cable is not going back to a modem but to a router.
Thanks.

 

[John Wunderlich]

what difference would there be if I disabled DHCP on the router I
purchased and simply plugged the wire from the building's router
into one of the available lan ports on my router? (I'd essentially
be using it as a switch, not as a router) And wouldn't there be a
conflict in having two routers on one lan. I understand about
private ips (192.168.x.x) vs public ips.

Wouldn't the building be
giving me a private ip and then my own router, the one I'd
purchase according to your scenario, would also give users an
address in the private, non-routable range?

Not if DHCP were disabled on your router.

The building's incoming cable is not going back to a modem but to
a router. Thanks.

I have a router that I use as a switch and there's nothing wrong
doing that. There is a little more to it than just disabling DHCP,
though.

If the Building's router and/or your router has auto-direction
sensing on the LAN ports, then you can just connect to a LAN port as
you described. Keep in mind though that the proper connection should
be made with a "cross-cable".

Also, your router, itself, has a LAN IP address (settings-
configurable, usually defaulting to 192.168.1.1 for Linksys) -- you
must make sure that this IP address does not conflict with any other
address on the building's network yet falls within the building's LAN
subnet mask. If your building's router uses the same address as your
router, you can bring down your whole building's internet connection.

HTH,
John

 

[Milo]

Thanks for your input. So if I do an ipconfig and confirm that the ip of my
router/switch does not match that of the gateway, I should be ok, right?
I'll try to connect with the tech who handles the building's router to find
out the range of private ip addresses in use, then assign a number in the
high end of the range to my router.

I still think the best thing for me to have is a dumb switch. No question of
duplicate DHCP, conflicting ip addresses, etc.

 

[John Wunderlich]

Thanks for your input. So if I do an ipconfig and confirm that the
ip of my router/switch does not match that of the gateway, I
should be ok, right? I'll try to connect with the tech who handles
the building's router to find out the range of private ip
addresses in use, then assign a number in the high end of the
range to my router.

I still think the best thing for me to have is a dumb switch. No
question of duplicate DHCP, conflicting ip addresses, etc.

Be careful. "ipconfig" will give you the address of the gateway that
assigned you your DHCP address. If you turn off DHCP, then you will
get the IP address of the gateway whose DHCP is still working.

Using a dumb switch is always safer, particularly if you aren't
comfortable with how routers are configured.

-- John