Win2K Internet Connection Sharing doesn't work, while XP does

H

H. Debs

I have a dual-boot PC with Win2K and WinXP. This PC is connected to
the internet via an ADSL modem (ethernet NIC). It is also connected
via Wireless to a LAN.
If I boot in XP and enable ICS, the other PCs connected to the
wireless LAN can connect normally to the internet.
If I boot in 2K and enable ICS, the other PCs only get 'partial'
connection to the internet. For example, they can get email via
Outlook and Outlook Express, they can go to private networks on the
internet via VPN, they can go search on google and some other web
sites, but they can't surf to many web sites (e.g. microsoft.com). The
browser just waits forever and says the site can't be reached. Note
that some sites can be reached!

What can be wrong with my Win2K installation? Note that the LAN
router and other PCs configurations are identical in both cases
(whether I boot into 2K or XP). It seems to be a dns or routing
problem.

I need to correct the problem under Win2K, because that is the OS I
boot to most of the time.

I checked which services are running on XP (SP1) and 2K (SP4) and
found that XP has some extra services running. I'm listing those which
I think are related to networking:

Application Layer Gateway Service
Background intelligent transfer service
Cryptographic services
Error reporting service
Network Location Awareness (NLA)
Secondary Logon
Shell Hardware detection
Terminal Services
Web Client

I have tried disabling my firewall (Kerio PF 2.1.5) completely under
Win2K, but it didn't solve the problem. I tried putting my ISP's DNS
server IPs directly on the other PCs, but it's still the same.

I had DNSKong (a little DNS server/filter) running under Win2K on my
PC. It shows in a little window which sites were requested from it.
When a PC on the LAN asks for google, it show it in the window. But
when a PC asks for Microsoft, it is not shown (of course I checked and
microsoft is not being filtered by it, and even if it were, the name
would still appear in the window, in red). It is as if some DNS reques
ts don't even reach DNSKong. Could it be something on the LAN PC?
I disabled DNSKong, but the situation is exactly the same.

My wireless connection was configured automatically (to 192.168.0.1)
when I set the ICS option on my modem connection.
I think I set up the wireless router properly (it is working well when
I boot XP). I disabled its DHCP server for it to work (it has an
integrated ADSL modem which is not connected to a phone line), and
assigned it a fixed IP (192.168.0.20). Again, the router is functiong
with XP ICS, without modification.

Any ideas?

Thanks a lot!

Habib
 
H

H. Debs

No-one knows the answer to this one?

I'll simplify it:
- Even without the router the problem is the same (just one laptop
connected wireless ad-hoc to the internet pc)
- Even without firewalls the problem is the same

The problem briefly: LAN with just 2 PCs, ethernet ADSL modem.
Wireless ad-hoc LAN.
- ICS doesn't fully work with W2K Pro - some things work (p2p, some
web sites like google.com, email send and receive with Outlook), some
things don't (mainly access to the majority of web sites - it seems to
be a DNS issue, but I don't have any DNS server running).
- It works perfectly if I boot under WinXP Pro.

I've been reading loads of documents even from microsoft KB and
followed instructions to the letter, but no luck.

Any ideas?

Thanks for your help!
 
H

H. Debs

I solved my problem. I don't know how, but I think it was
uninstalling and reinstalling the TCP/IP protocol that did it.
 
H

H. Debs

Sorry, uninstalling and resinstalling TCP/IP protocol didn't correct
the problem.
The problem was caused by the fact that the Win2K machine with the
internet connection was configured such that all interfaces (NICs) had
an MTU of 1492, which the machine on the LAN had an MTU of 1500. I had
not changed the MTU for my WinXP boot, so that was still 1500. That's
why it worked fine when I booted under XP and not under Win2K.
I solved the problem by configuring the LAN machine to also have an
MTU of 1492.

As to why with such a configuration (MTU=1492 on the machine connected
to the internet and MTU=1500 on the LAN machine), the LAN machine was
able to perfectly get some web sites but not at all others, that
remains a total mystery to me.

(case closed) :)

Habib
 

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