Comcast static IPs through router

Have a question or want to start a discussion? Post it! No Registration Necessary.  Now with pictures!

Threaded View


I have 5 static IPs from Comcast through an SMC 8013WG cable modem. I
need to route 4 of these IPs to static IPs on my LAN. What do I need in
the way of hardware/software? One of the 5 WAN IPs goes directly to my
mail server.


Re: Comcast static IPs through router


duncan wrote:
Quoted text here. Click to load it

First, this is an IP question, not an ethernet question.

I usually use FreeBSD, or some other free unix-like system
for a router.  (A 486 is fast enough, though a pentium
would probably be more reasonable these days.)
I don't believe that most SOHO routers include
this ability, though it isn't hard to do.

As I understand it the Linksys WRT54G is one that people use to
load linux on, in which case it might be that you could do it.

-- glen


Re: Comcast static IPs through router



Quoted text here. Click to load it

The WRT54G permits only one WAN IP, AFAIK.  The latest WRT54G version is no
longer using Linux, but older ones are.  The WRT54GS is still available
with Linux firmware.

There is several 3rd party firmware for the linux based versions, but I
don't know if they add this capability.


Re: Comcast static IPs through router


John Gray wrote:
(snip)

Quoted text here. Click to load it

Sorry, I meant loading linux on it downloading to flash, not the
software it comes with (which may also be Linux).

Quoted text here. Click to load it

I don't know either, but it is common in linux NAT software, so I
would be surprised if there was one that would.

-- glen


Re: Comcast static IPs through router


Quoted text here. Click to load it

My U.S. Robotics USR 5462 SoHo (4 port switch with 802.11g)
allows mapping 8 WAN addresses to LAN (internal/local) addresses.
I'm unsure the "DMZ" option will work
since that might not pass thru the WAN address.
Sadly, that model is already at "end of life",
the last firmware update being Sept 2004.

I'm unsure what other SoHo NAT/switches have that option.
My equipment is already several years old.
--

-- mejeep deMeep ferret!

Re: Comcast static IPs through router


Jeff Jonas wrote:
Quoted text here. Click to load it

The Netopia R9100 will do it. The R910 also. These were enterprise unit
"back in the day" I bought several of them to do just this for my client
a few years ago off ebay. At the time they were about $200. Now they
seem to cost about $75 or less plus shipping on ebay.

Load up the current firmware, (about 4 years old), and they work fine.
Interface is a wee bit arcane to say the least but as long as your
connection isn't more than about 5mbps you'll be fine. I still have
several running and they just keep on ticking.


Re: Comcast static IPs through router


Quoted text here. Click to load it

I don't know any SoHo router that will route 5 IPs,
or where NAT can be disabled.  I see three alternatives:

1)  Buy a commercial-duty router (Crisco);
2)  Build a *BSd/Linux router (LRP?)
3)  Hang a _switch_ onto the modem, not a router!

For (3) the 4 static boxes will have to be hardened because they
will be directly visible (no firewall).  The 5th IP will probably
be needed for a typical router to do NAT and manage the modem.

It might be possible to insert router per static machine if you
want the HW firewalling (ie, the machines are running MS-Windows).
5 routers total hanging off the switch, hanging off the modem.

-- Robert



Re: Comcast static IPs through router


Quoted text here. Click to load it
 
Quoted text here. Click to load it

Yes, that was my next suggestion.  Put a switch on the modem, and
then four routers off of that.  You might find some used routers,
or even new ones for a low enough price that it makes more sense.

-- glen

Site Timeline