Comcast broadband, router: only one PC at a time

Comcast broadband, router: only one PC at a time

Post by Morris Ebb » Thu, 06 Oct 2005 01:28:58


Just got married and moved in with my wife, who has Comcast cable broadband.
(Had previously been on Verizon DSL.) She has a Motorola SB1500 SURFboard
cable modem and a LINKSYS BEFSR41 router; runs Windows XP Home. (Pretty
sure it's SP2.)

Looking at the quick setup guide for the router, I tried plugging my Windows
XP Home SP2 box in. Didn't work. Tried a few things, then finally got it
to work when I found that I can get one computer (but not both) running
broadband. Pattern seems to be that the one I plug into port 1 (or whatever
it's called) on the router works, but not the other.

Any suggestions on how I can get both to work simultaneously? I did some
web/USENET searches on this, and can't quite figure it out. (I went to the
admin web page for the router, and it says it's set up for 50 PCs, not
merely 1.)

TIA,

S
 
 
 

Comcast broadband, router: only one PC at a time

Post by Bill M » Thu, 06 Oct 2005 02:29:44

On Tue, 4 Oct 2005 12:28:58 -0400, "Morris Ebbets"



The cable modem is probably a SB5100, I hope. :)


Not much to go on here, but the basics are that the router's Internet
port, sort of off to one side by itself, should be connected to the
cable modem, and the PC(s) should be connected to any of the ports
labeled 1-4. The PC(s) should be configured for DHCP, (easiest to get
working; you can do static IP assignment outside of the router's DHCP
range later.) Power down the cable modem, the router, and the PC(s),
then power up the cable modem and let it stabilize, power up the
router and let it stabilize, then power up one PC at a time. Make sure
there are Link lights at both ends of all live (powered up) cables.
Rule out a bad patch cable. If Port 1 works on the router, but 2-4
don't, you may have a bad router. If you have all of the necessary
Link lights, see if you can ping the LAN side of the router from the
'bad' PC, (usually at 192.168.1.1), and if that works, ping the cable
modem, (usually at 192.168.100.1). The ping results will help you
determine where to go next.

--
Bill

 
 
 

Comcast broadband, router: only one PC at a time

Post by $Bil » Thu, 06 Oct 2005 02:30:37


Are you using a straight through cable or a crossover cable ?
Did you try re-booting the PC ? It should pick right up on any
of the ports.
 
 
 

Comcast broadband, router: only one PC at a time

Post by Tom Stille » Thu, 06 Oct 2005 02:44:22

In article <f5y0f.77$ XXXX@XXXXX.COM >,



A couple of things. The cable modem should be plugged into the "WAN"
port and port 1 is connected internally, but with reversed directional
sense, to the "Uplink" port

If the router has DHCP enabled, you should configure your computers to
seek a DHCP IP assignment from IP address 192.168.1.1. If DHCP is not
enabled, manually assign the computers IP addresses in the range
192.168.1.[1..254]

You should also specify the router's address (192.168.1.1) as the DNS
server.

--
Tom Stiller

PGP fingerprint = 5108 DDB2 9761 EDE5 E7E3
7BDA 71ED 6496 99C0 C7CF
 
 
 

Comcast broadband, router: only one PC at a time

Post by Bill M » Thu, 06 Oct 2005 03:02:29

On Tue, 04 Oct 2005 13:44:22 -0400, Tom Stiller




I don't think the BEFSR41 has that relationship between Port 1 and the
WAN (Internet) port, and there is no "Uplink" port. Some older
equipment was like that, though.


Eek! <g> 192.168.1.1 is already in use by the router's LAN port, so
your example for the computers should be 192.168.1.[2..254].


Sorry to be nit picky, I'm just trying to avoid confusion.

--
Bill
 
 
 

Comcast broadband, router: only one PC at a time

Post by David H. L » Thu, 06 Oct 2005 03:02:36

From: "Tom Stiller" < XXXX@XXXXX.COM >


| A couple of things. The cable modem should be plugged into the "WAN"
| port and port 1 is connected internally, but with reversed directional
| sense, to the "Uplink" port
|
| If the router has DHCP enabled, you should configure your computers to
| seek a DHCP IP assignment from IP address 192.168.1.1. If DHCP is not
| enabled, manually assign the computers IP addresses in the range
| 192.168.1.[1..254]
|
| You should also specify the router's address (192.168.1.1) as the DNS
| server.
|
| --
| Tom Stiller
|
| PGP fingerprint = 5108 DDB2 9761 EDE5 E7E3
| 7BDA 71ED 6496 99C0 C7CF

You mean the range is; 192.168.1.2 ~ 192.168.1.254 ( 192.168.1.[2..254] )

191.168.1.1 is reserved by the Router.

The Linksys BEFSR41 does not have DNS Daemon and thus 191.168.1.1 should not be entered
into the DNS settings of the platform. That should be manually entered based upon what the
Comcast segment provides or better yet, Enable DHCP on the platform such that it gets the
complete stack, including the Comcast DNS servers, via DHCP.

--
Dave
http://www.yqcomputer.com/
http://www.yqcomputer.com/
 
 
 

Comcast broadband, router: only one PC at a time

Post by Tom Stille » Thu, 06 Oct 2005 03:16:33

In article <0tz0f.225$Ll2.196@trnddc04>,



Yep! I fumble-fingered that one.

Well, my old BEFSR41 captures the ISP (Comcast) supplied DNS addresses.
All the computers on my local network have manually assigned IP
addresses and specify 192.168.1.1 as their DNS entry. I have no problem
resolving URLs on any of them.

--
Tom Stiller

PGP fingerprint = 5108 DDB2 9761 EDE5 E7E3
7BDA 71ED 6496 99C0 C7CF
 
 
 

Comcast broadband, router: only one PC at a time

Post by Morris Ebb » Thu, 06 Oct 2005 04:05:57


broadband.
SURFboard

Right you are.

Windows
it
whatever

I'm pretty sure it's not a configuration issue, because my XP box works when
hooked up to port 1, and I'm pretty sure that it's running DHCP.


OK. Did all that.


Don't think it's the cable since P 1 works, but not 2-4.


Good idea. That's my leading hypothesis right now.


Forgot to do that...see my response to the entire thread for the info I
*did* gather.
 
 
 

Comcast broadband, router: only one PC at a time

Post by Morris Ebb » Thu, 06 Oct 2005 04:06:26


broadband.
SURFboard
Windows
it
whatever
some
the

Straight.


I've cycled a number of times. Works on Port 1 but not 2-4.
 
 
 

Comcast broadband, router: only one PC at a time

Post by Morris Ebb » Thu, 06 Oct 2005 04:13:15


broadband.
Windows
whatever
the

Thanks, all, for the kind and informative replies.

As I mentioned in some of my comments to specific replies, I tried it again,
this time only hooking up my XP box and not my wife's. (I was careful to
power everything off, then power the modem on, let it stabilize, then power
the router on, and then the PC, for each cycle.)

Things work fine when I'm connected to Port 1; they don't work when
connected to ports 2, 3, or 4.

One odd thing: on ports 2-4, while I can't download web pages, it seems I
can ping out, e.g. yahoo. The tracert to yahoo on e.g. port 4 was pretty
much the same as that on port 1 (though not quite the same; not sure if
that's because yahoo sends you to different IP addresses on a random
basis...for port 1 it went to [216.109.112.135], for port 4, to
[66.94.234.13]).

The output of ipconfig /all was the same for all four ports (except for the
specifics of the DHCP lease). Here it is for port 1:
Windows IP Configuration
Host Name . . . . . . . . . . . . : apollo
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Unknown
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
DNS Suffix Search List. . . . . . : hsd1.md.comcast.net.
Ethernet adapter Local Area Connection 2:
Connection-specific DNS Suffix . : hsd1.md.comcast.net.
Description . . . . . . . . . . . : NETGEAR FA311 Fast Ethernet
Adapter
Physical Address. . . . . . . . . : 00-02-E3-24-AC-B3
Dhcp Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IP Address. . . . . . . . . . . . : 192.168.1.100
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.1.1
DHCP Server . . . . . . . . . . . : 192.168.1.1
DNS Servers . . . . . . . . . . . : 68.87.64.196
68.87.66.196
68.48.0.13
Lease Obtained. . . . . . . . . . : Tuesday, October 04, 2005
2:26:09 PM
Lease Expires . . . . . . . . . . : Wednesday, October 05, 2005
2:26:09 PM

At this point my best guess is that which one of you suggested, namely, a
bad router...

Any further thoughts?

Thanks again,

S
 
 
 

Comcast broadband, router: only one PC at a time

Post by David H. L » Thu, 06 Oct 2005 04:46:16

From: "Tom Stiller" < XXXX@XXXXX.COM >


|
| Well, my old BEFSR41 captures the ISP (Comcast) supplied DNS addresses.
| All the computers on my local network have manually assigned IP
| addresses and specify 192.168.1.1 as their DNS entry. I have no problem
| resolving URLs on any of them.
|
| --
| Tom Stiller
|
| PGP fingerprint = 5108 DDB2 9761 EDE5 E7E3
| 7BDA 71ED 6496 99C0 C7CF


Well Tom I tested it on my BEFSR81 and you are correct !
That is news to me and I have installed too many BEFSR41 (Model v1, v2 and v3) to keep track
of ;-)

Thanx for the correction.

Mea culpa !

--
Dave
http://www.yqcomputer.com/
http://www.yqcomputer.com/
 
 
 

Comcast broadband, router: only one PC at a time

Post by Dave » Thu, 06 Oct 2005 04:59:44

I ran multiple pc's using that same router before I upgraded to wireless. I
didn't have to do anything except make sure the router and all pc's were
configured for DHCP. You might want to do a reset of the router to get it
back to factory settings in case osmething has been changed. Then just
make sure it's set for DHCP. Check the pc's for DHCP too.
 
 
 

Comcast broadband, router: only one PC at a time

Post by Tom Stille » Thu, 06 Oct 2005 05:22:54

In article <c_A0f.4802$BU1.1939@trnddc06>,



You're welcome. I know I've made my share of mistakes and that's the
primary reason why I like public newsgroups and open source software;
there are always sharp-eyed observers to see that the emperor is fully
clothed ;-)

--
Tom Stiller

PGP fingerprint = 5108 DDB2 9761 EDE5 E7E3
7BDA 71ED 6496 99C0 C7CF
 
 
 

Comcast broadband, router: only one PC at a time

Post by Tom Stille » Thu, 06 Oct 2005 05:46:56

In article <fvA0f.81$ XXXX@XXXXX.COM >,



Before replacing the router, you might download and install the latest
firmware from the support page at <http"//linksys.com>

--
Tom Stiller

PGP fingerprint = 5108 DDB2 9761 EDE5 E7E3
7BDA 71ED 6496 99C0 C7CF
 
 
 

Comcast broadband, router: only one PC at a time

Post by Bill M » Thu, 06 Oct 2005 07:50:12

On Tue, 4 Oct 2005 15:13:15 -0400, "Morris Ebbets"



I just checked my own router to see if it had the option to disable
certain ports in the QoS config, but it only allows ports to be set at
a High or Low priority. I don't see anything about completely
disabling them, and I assume yours is the same. Even so, as has been
suggested, it probably wouldn't hurt to do a full reset to put
everything back to factory defaults. Either stick a paper clip into
the reset hole or reset it via the Admin page.

So far, it was sounding like ports 2-4 are dead, but you said ping
works through each of them, so they aren't dead after all. *shrug*

--
Bill