TCP/IP setting changes

I've seen two computers on the same network - one with 98SE and one with
XP - that switched from static IP addressing to automatic. This is on a
peer-to-peer network with no DHCP server. So, the IP addresses become the
169... automatically assigned default numbers.

What might cause this to happen? It's most unexpected and, of course, stops
network access entirely to the computer on which it occurs.

Thanks,

Fred




Fred Marshall

In article <#(E-Mail Removed)>, "Fred Marshall"
<fmarshallx@remove_the_x.acm.org> wrote:
>I've seen two computers on the same network - one with 98SE and one with
>XP - that switched from static IP addressing to automatic. This is on a
>peer-to-peer network with no DHCP server. So, the IP addresses become the
>169... automatically assigned default numbers.
>
>What might cause this to happen? It's most unexpected and, of course, stops
>network access entirely to the computer on which it occurs.
>
>Thanks,
>
>Fred

That's how it's supposed to work on a network with no DHCP server.
The computers assign themselves compatible APIPA (Automatic Private IP
Address) addresses in the 169.254.x.x. range that's reserved for
exactly that use.

Why do you say that it stops network access? The computers should be
able to see each other, share files and printers, etc, using APIPA.
--
Best Wishes,
Steve Winograd, MS-MVP (Windows Networking)

Please post any reply as a follow-up message in the news group
for everyone to see. I'm sorry, but I don't answer questions
addressed directly to me in E-mail or news groups.

Microsoft Most Valuable Professional - Windows Networking
http://mvp.support.microsoft.com

Steve Winograd's Networking FAQ
http://www.bcmaven.com/networking/faq.htm

Steve,

Thanks for the reply.

Well, all of the machines have static addresses in 192.168.1.x. Presumably
one does not need a DHCP server with static addresses - two different
things.

So, if just *one* of the machines switches all by itself to APIPA with a 169
address, it isn't on the same "network" and doesn't see the other
192.168.1.x machines and vice versa.

It now appears that the only machines that switched like this were XP
machines.

Fred

"Steve Winograd [MVP]" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> In article <#(E-Mail Removed)>, "Fred Marshall"
> <fmarshallx@remove_the_x.acm.org> wrote:
> >I've seen two computers on the same network - one with 98SE and one with
> >XP - that switched from static IP addressing to automatic. This is on a
> >peer-to-peer network with no DHCP server. So, the IP addresses become
the
> >169... automatically assigned default numbers.
> >
> >What might cause this to happen? It's most unexpected and, of course,
stops
> >network access entirely to the computer on which it occurs.
> >
> >Thanks,
> >
> >Fred
>
> That's how it's supposed to work on a network with no DHCP server.
> The computers assign themselves compatible APIPA (Automatic Private IP
> Address) addresses in the 169.254.x.x. range that's reserved for
> exactly that use.
>
> Why do you say that it stops network access? The computers should be
> able to see each other, share files and printers, etc, using APIPA.
> --
> Best Wishes,
> Steve Winograd, MS-MVP (Windows Networking)
>
> Please post any reply as a follow-up message in the news group
> for everyone to see. I'm sorry, but I don't answer questions
> addressed directly to me in E-mail or news groups.
>
> Microsoft Most Valuable Professional - Windows Networking
> http://mvp.support.microsoft.com
>
> Steve Winograd's Networking FAQ
> http://www.bcmaven.com/networking/faq.htm

In article <#(E-Mail Removed)>, "Fred Marshall"
<fmarshallx@remove_the_x.acm.org> wrote:
>>>I've seen two computers on the same network - one with 98SE and one with
>>>XP - that switched from static IP addressing to automatic. This is on a
>>>peer-to-peer network with no DHCP server. So, the IP addresses become the
>>>169... automatically assigned default numbers.
>>>
>>>What might cause this to happen? It's most unexpected and, of course, stops
>>>network access entirely to the computer on which it occurs.
>>>
>>>Thanks,
>>>
>>>Fred
>>
>>That's how it's supposed to work on a network with no DHCP server.
>>The computers assign themselves compatible APIPA (Automatic Private IP
>>Address) addresses in the 169.254.x.x. range that's reserved for
>>exactly that use.
>>
>>Why do you say that it stops network access? The computers should be
>>able to see each other, share files and printers, etc, using APIPA.
>
>Steve,
>
>Thanks for the reply.
>
>Well, all of the machines have static addresses in 192.168.1.x. Presumably
>one does not need a DHCP server with static addresses - two different
>things.
>
>So, if just *one* of the machines switches all by itself to APIPA with a 169
>address, it isn't on the same "network" and doesn't see the other
>192.168.1.x machines and vice versa.
>
>It now appears that the only machines that switched like this were XP
>machines.
>
>Fred

Fred,

I'm sorry, but I must have missed where you said that the computers
switched themselves from static addresses to APIPA. That shouldn't
happen, and I don't know what could cause it.
--
Best Wishes,
Steve Winograd, MS-MVP (Windows Networking)

Please post any reply as a follow-up message in the news group
for everyone to see. I'm sorry, but I don't answer questions
addressed directly to me in E-mail or news groups.

Microsoft Most Valuable Professional - Windows Networking
http://mvp.support.microsoft.com

Steve Winograd's Networking FAQ
http://www.bcmaven.com/networking/faq.htm