Lan Connectivity Problems

[sbk]

I have two computers connected by LAN to a DSL Router (surecom) with 4 ports. From time to time I connect my laptop or my friend connects his laptop. One PC and my laptop both receive full connectivity. The other PC and my friends laptop have limited (ie the internet doesn't work). As near as I can tell, the settings on all 4 computers are the same.

I have the router set up as a DHCP server, all computers obtain their IP addresses automatically.

Why oh why does it work on two computers but not on the other two?

***edit***

Forgot to add, when my non-working pc and my friend's laptop are connected to someone else's DSL, they work.

And yes, I have tried different cables. I have unplugged the working cable out of the pc that works and plugged it into the laptop, and it still doesn't work

**also, I have a TT&T line, ji-net internet, all 4 computers are running WinXP**

[cdnvic]

Take a look in the router's setting to make sure MAC Address Filtering is not enabled. That would block computers not specificly allowed from connecting to the network. The firewall may also not be allowing the other two machines' ip addresses access to the WAN (Internet).

[sbk]

Hey Cdnvic, glad to see you again

I use Zonealarm on both my PC's and my laptop.

I have connected my laptop at the same time as the other pc and they both work. I have connect my other PC at the same time as the working pc and only the working pc works. Wouldn't it not work for all of them if it were a setting in the router?

[sbk]

Mac spoofing is disabled

DHCP client is not enabled but DHCP server is

[cdnvic]

Sounds like mac address filters to me. This will read the the fixed mac address of the network card and compare it to allowed addresses. I used to use them in a guesthouse to keep guests from logging their laptops into the office dsl at night.

Also make sure your firewall settings (inside the router, not zone alarm) allow all four IPs to connect to the WAN. Sounds like it may have rules setup for only two IP addresses as that was what was on the network when it was setup.

[sbk]

Ok, how to?

**note bridge filtering is not allowed-- is this what I am looking for? the mac address is set to a bunch of zeros**

forgot to add, even when only the one working PC is connected the only one other one that can connect is my laptop

Edited November 18, 2006 by sbk

[cdnvic]

To access the firewall settings in the router go to 192.168.0.1 in your browser and enter your username/password. If only two specific machines work on it then it's almost certainly a MAC address issue. Sorry I can't go much further but I haven't worked with these routers before. I'd try the surecom forum to get the specific steps to adjusting the settings.

http://surecom-forums.no-ip.biz:8001/auth/phpBB2/index.php

If you need some clarifications I'd be happy to help when I get up but it's 1am now and I'm about to fall asleep at the keyboard (again ).

[sbk]

Thanks, I'll wait, but to let you know, that isn't the address of my router, and it doesn't appear to have a firewall built in (no SPI listed)

[astral]

Check the other computers are set to accept the address given by DHCP.

ie don't have an ip address specified.

In the Network set up, make sure the other computers have the right

DNS settings.

[RBO]

This behavior can also be caused by some cheap network cards, which have wrong or no MAC adresses at all. Usually, you can override this setting in the network adapter properties.

Good luck!

[King Dong]

This behavior can also be caused by some cheap network cards, which have wrong or no MAC adresses at all. Usually, you can override this setting in the network adapter properties.

Good luck!

[sbk]

Both the pc and the laptop that do not work on my router work on other routers. The laptop belonging to my friend (which doesn't work) is an Acer as is mine (which does work on my router).

All 4 computers have the IP address and DNS assigned automatically. As near as I can tell all 4 are set up identically, just two of them don't have any connectivity.

[cdnvic]

What's the exact model of your router? That will make diagnosis easier.

[sbk]

Surecom EP 4704 SX annex A

I know how to get into the router, just not sure what I am looking for!

[cdnvic]

I can't find a manual for it but I think if you reset the router (stick a toothpick or something in the little hole at the back) and run the configureation wizard with all of them hooked up it might set things up for having four machines on it.

First get into the router and look for anything that says "enable mac address filtering" and turn that off. Everything I've seen points to this being the problem. A search through a bunch of support forums pretty much backs it up as well. Try this before resetting anything as it will likely solve the problem.

Edited November 19, 2006 by cdnvic

[sbk]

Mac spoofing is disabled, is that the same thing? And then in bridge filtering it shows this:

Enable Bridge Filtering: No

ID Source MAC* Destination MAC* TYPE**

1

Block Forward

* MAC address should looks like 000002fa6fab

** TYPE is Ethernet type should looks like a5ff

Number of Bridge Filters 0

and then in Learned Mac table:

Bridge MAC Table

MAC Address Expiration

00:0B:6A:D1:BA:34 100

Aging Timeout: 100 Seconds

[khunyae]

... reset the router (stick a toothpick or something in the little hole at the back) and run the configureation wizard with all of them hooked up...

The above quoted reply is the same advice that I would give. Reading the above posts, and especially the fact that your router is assigned a non-standard address (standard addresss is 192.168.0.1) I am sure that your router is not at default settings.

Someone has changed some standard settings resulting in your difficulty to connect four machines. The simplest answer is IP address range - check in DHCP server settings to see range if IP addresses that are to be assigned. This would normally be 1-256 ie 256 possible addresses. Your router may be limited to only assigning a few IP addresses. You need a minimum of 5 - one for the router and one for each of your machines.

Edited November 19, 2006 by khunyae

[sbk]

That is the router address in the manual.

The assigned IP range I reset to about 30 addresses, but when I manually assign the IP address to my friends laptop, it does see the router at that point but won't access the web.

[sbk]

khunyae and cdnvic, thank you thank you thank you! You made me realize something about the IP range, it was still set at system allocated even though I had adjusted the IP range, I forgot to check the little button that says "user defined". When it hit me, I changed it and now it works!

Love you guys!!!

[khunyae]

That is the router address in the manual.

The assigned IP range I reset to about 30 addresses, but when I manually assign the IP address to my friends laptop, it does see the router at that point but won't access the web.

What is the IP address that your router can be "seen" at?

What is the IP address and subnet range that you are assigning?

What is the IP address of each of your four machines?

[khunyae]

khunyae and cdnvic, thank you thank you thank you! You made me realize something about the IP range, it was still set at system allocated even though I had adjusted the IP range, I forgot to check the little button that says "user defined". When it hit me, I changed it and now it works!

Love you guys!!!

Excellent.

[cdnvic]