TCP/IP Loopback

[welshguy]

Hi Guys,

Hopefully someone can give me some clues on this problem.

Small home net lab - Three servers, One PC (2000 Prof), ADSL connection through a ADSL router (10mb)and a laptop connected through a wireless card and Access point.

Now my problem - I cannot ping PC1 from the laptop.
The link is fine as the laptop can ping other servers connected to same hub.
Checked cables, static routes, NICs and arp tables - all fine.

But on investigation found that PC1 cannot
a) ping it's own loopback
b) ping it's own IP address
but can ping other servers (including laptop)

I have changed NIC, cables etc, cleared arp tables, route tables etc. Removed TCP/IP - reinstalled. All IP addresses/subnets correct as well.

Basically can't think of what else to do apart from reinstall OS but won't find out what's wrong that way.
Any ideas that I've missed, been dealing with these sort of problems for years but this one's got me stumped :-(

Cheers

 

[GlenJohnson]

Have you checked your hosts and lmhosts files? If you have an old one with the wrong IP's it could cause problems. Glen A. Johnson
Microsoft Certified Professional
gjohn76351@msn.com
"Time past and time future
What might have been and what has been
Point to one end, which is always present".
T. S. Eliot (1888-1965), Anglo-American poet.

 

[welshguy]

Glen,

Yes checked this and they're ok - but I get my problem with pinging IP addresses as well as names.

Thanks for the suggestion though

 

[GlenJohnson]

What operating systme on Laptop? If it's XP, it's notorious for bad networking. You might run ipconfig /all and see what you get. If it looks normal post the settings for others to see. Might get an awnser that way. Glen A. Johnson
Microsoft Certified Professional
gjohn76351@msn.com
"Time past and time future
What might have been and what has been
Point to one end, which is always present".
T. S. Eliot (1888-1965), Anglo-American poet.

 

[welshguy]

Laptop is on Win2000 now although still had same problem with 98. I think the problem is to do with the PC - the very fact that it cannot ping it's loopback address or it's own IP suggests something wrong with TCP/IP stack - I think.

It can ping other servers on my network though. I'm looking at reinstalling OS at the moment but hate doing this as the mystery will die for ever :-(

I have had trouble getting any packet trace programs running as well so this might be linked. Programs I use all the time like Iris and netmon won't bind to the adapter even though it's had three different Nics now !!

Thanks again for your input !!

 

[katamann]

Hi

Have the PC had any firewall software installed and later removed?

-katamann

 

[Guest_imported]

Hi,

Could someone tell me what is IP addressing and subnetting is all about or give me a good website.

Guru (guru_kiranus@hotmail.com)

 

[wybnormal]

IP addressing is the fine black art of making working networks talk IP. It's a logical addressing scheme based on binary.. ie.. 1's and 0's. We mere mortals use decimal.. ie.. 192.168.50.1 There is also a subnet mask which in programmese is ANDed to the IP address to get the subnet and number of hosts.

To get more info..

http://www.packetattack.com/tutorials.html

I have few links to tutorial sites for IP black magic ;-)

MikeS
Find me at

http://www.packetattack.com

"The trouble with giving up civil rights is that you never get them back"

 

[GlenJohnson]

Gooiee, have you tried http:

http://www.learntcpip.com

or learndns.com. Free sites. Glen A. Johnson
Microsoft Certified Professional
gjohn76351@msn.com

"Thought is the seed of action."
Ralph Waldo Emerson (1803-82); U.S. essayist and poet.