IP Conflict

[Neal]

I am having trouble on out network with people using
other peoples IP's I was wondering if there is a way I
can tell people to easily get the MAC address of the
person that is doing it. The people that are using the
computers for teh most part know nothing other then there
usual things such as E-Mail and word. I know in Win98 it
will automatically tell you the MAC address is this
possible on XP?

Thanks Neal

[CheshireCat]

"Neal" > wrote in message
...
> I am having trouble on out network with people using
> other peoples IP's I was wondering if there is a way I
> can tell people to easily get the MAC address of the
> person that is doing it. The people that are using the
> computers for teh most part know nothing other then there
> usual things such as E-Mail and word. I know in Win98 it
> will automatically tell you the MAC address is this
> possible on XP?
>
> Thanks Neal

What do you mean "with people using other peoples IPs"?
If your network has a DHCP server and you need to set up some people with
static IP addresses then make a note of the MAC addresses of these
particular PCs, set their PC IP addresses to static ones and reserve the
IP/MAC combination on the DHCP server.
If you dont tell the DHCP server which address/MACs to reserve then it WILL
give these addresses to someone else.

>-----Original Message-----
>
>"Neal" > wrote in message
...
>> I am having trouble on out network with people using
>> other peoples IP's I was wondering if there is a way I
>> can tell people to easily get the MAC address of the
>> person that is doing it. The people that are using the
>> computers for teh most part know nothing other then
there
>> usual things such as E-Mail and word. I know in Win98
it
>> will automatically tell you the MAC address is this
>> possible on XP?
>>
>> Thanks Neal
>
>What do you mean "with people using other peoples IPs"?
>If your network has a DHCP server and you need to set up
some people with
>static IP addresses then make a note of the MAC
addresses of these
>particular PCs, set their PC IP addresses to static ones
and reserve the
>IP/MAC combination on the DHCP server.
>If you dont tell the DHCP server which address/MACs to
reserve then it WILL
>give these addresses to someone else.
>
>
>.
>


I don't wanna do that because the computers that sue the
MAC address change on a regular bases... but the IP's
need to stay with the jack in the wall.

[CheshireCat]

> wrote in message
...
>
> >-----Original Message-----
> >
> >"Neal" > wrote in message
> ...
> >> I am having trouble on out network with people using
> >> other peoples IP's I was wondering if there is a way I
> >> can tell people to easily get the MAC address of the
> >> person that is doing it. The people that are using the
> >> computers for teh most part know nothing other then
> there
> >> usual things such as E-Mail and word. I know in Win98
> it
> >> will automatically tell you the MAC address is this
> >> possible on XP?
> >>
> >> Thanks Neal
> >
> >What do you mean "with people using other peoples IPs"?
> >If your network has a DHCP server and you need to set up
> some people with
> >static IP addresses then make a note of the MAC
> addresses of these
> >particular PCs, set their PC IP addresses to static ones
> and reserve the
> >IP/MAC combination on the DHCP server.
> >If you dont tell the DHCP server which address/MACs to
> reserve then it WILL
> >give these addresses to someone else.
> >
> >
> >.
> >
>
>
> I don't wanna do that because the computers that sue the
> MAC address change on a regular bases... but the IP's
> need to stay with the jack in the wall.

Hi Neil

The MAC address is The Global Unique Identifier for a network card, embedded
in its firmware, and unless the users keep swapping out their network cards
then that MAC will be individual to that PC. The wall sockets are not
intelligent.

Which software are you using for your DHCP server?
A DHCP server assigns IP addresses to client PC(network cards) that attempt
to connect to the network. The DHCP server finds an unused IP, returns it
to the new client and stores the IP/MAC combination in a table, dead simple.
Reservations are the term used for IP/MAC pairs stored in a second table. If
an IP address is "reserved" then it wont be given to a client unless that
client has the correct MAC address.
You should be able to query a good DHCP server for its current client IP/MAC
table. This table should contain values such as
"22-31-66-0D-10-C5" ,"192.168.0.3"
If the IP/MAC combination has been "reserved" then it will probably give you
a text description too eg "CheshireCats PC".
There will be a table entry for every PC using DHCP at that moment.

Your original message suggested that some users are getting a message that
their IP is already in use, have you checked to see if these users have been
configured to have a static IP address?
No user should have a static IP address unless their machines have been
registered with the DHCP server. Im not too sure but I think it shouldnt be
necessary for any user to have a static IP if their MAC has been reserved.

[Bob Willard]

wrote:
>>-----Original Message-----
>>
>>"Neal" > wrote in message
...
>>
>>>I am having trouble on out network with people using
>>>other peoples IP's I was wondering if there is a way I
>>>can tell people to easily get the MAC address of the
>>>person that is doing it. The people that are using the
>>>computers for teh most part know nothing other then
>
> there
>
>>>usual things such as E-Mail and word. I know in Win98
>
> it
>
>>>will automatically tell you the MAC address is this
>>>possible on XP?
>>>
>>>Thanks Neal
>>
>>What do you mean "with people using other peoples IPs"?
>>If your network has a DHCP server and you need to set up
>
> some people with
>
>>static IP addresses then make a note of the MAC
>
> addresses of these
>
>>particular PCs, set their PC IP addresses to static ones
>
> and reserve the
>
>>IP/MAC combination on the DHCP server.
>>If you dont tell the DHCP server which address/MACs to
>
> reserve then it WILL
>
>>give these addresses to someone else.
>>
>>
>>.
>>
>
>
>
> I don't wanna do that because the computers that sue the
> MAC address change on a regular bases... but the IP's
> need to stay with the jack in the wall.

If you want the IPA to stay with the physical location, here's an
easy but not free solution: provide every wall jack with a router,
give each router a static IPA, and tell users to plug their PCs
into the router's LAN-side instead of the jack. The PCs will then
get their local IPA from the router, and the rest of the network
will see only the IPA of the router as the PC's IPA, due to NAT.
--
Cheers, Bob