Problem with a fixed-IP address in the LAN

I have a wired LAN and router with integrated switch.
The network is configured as peer-to-peer windows workgroup with many
different systems: WinXP, NT4, Win2000, Win95 and Win98SE.

The router offers DHCP feature: thus I have configured some PCs in order
to get automatically the IP address, some other PCs must have instead a
fixed IP. Well till now all work fine.

I have now a Win98SE notebook: it works in the LAN only if I set "Obtain
an IP address automatically".
On the other hand if I set "Specify an IP address" and give a compatible
address I cannot access shared resource in the LAN. I can see the are PC
of the LAN in explorer "network neighborhood", but if I click on the
PC-name then I get no access. Moreover from a DOS box I cannot ping the
other PCs.

I tried changing the IP address (using always free addresses), but I got
no results. In my LAN I have other win95 and win98 PCs with fixed
IP-address. I repeated for this notebook the same network configuration
as for those Win9x PCs, but i do not understand why it does work only
with automatic IP and not with fixed IP-Address.

Any suggestion?

Thank you for replying.
Gio

Giobibo wrote:

> I have a wired LAN and router with integrated switch.
> The network is configured as peer-to-peer windows workgroup with many
> different systems: WinXP, NT4, Win2000, Win95 and Win98SE.
>
> The router offers DHCP feature: thus I have configured some PCs in order
> to get automatically the IP address, some other PCs must have instead a
> fixed IP. Well till now all work fine.
>
> I have now a Win98SE notebook: it works in the LAN only if I set "Obtain
> an IP address automatically".
> On the other hand if I set "Specify an IP address" and give a compatible
> address I cannot access shared resource in the LAN. I can see the are PC
> of the LAN in explorer "network neighborhood", but if I click on the
> PC-name then I get no access. Moreover from a DOS box I cannot ping the
> other PCs.
>
> I tried changing the IP address (using always free addresses), but I got
> no results. In my LAN I have other win95 and win98 PCs with fixed
> IP-address. I repeated for this notebook the same network configuration
> as for those Win9x PCs, but i do not understand why it does work only
> with automatic IP and not with fixed IP-Address.
>
> Any suggestion?
>
> Thank you for replying.
> Gio

Perhaps you entered an incompatible netmask.

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> Perhaps you entered an incompatible netmask.

Sure this PC is not clashing with one given the same IP address through
DHCP?

Also, did you know that you can get DHCP to reserve a specific address for a
specific machine (actually specific MAC address on the network card in that
machine)? This can allow you to set all machines the "DHCP" but ensure that
specific machines always get the same IP address.

Paul DS.

CJT wrote:

> Perhaps you entered an incompatible netmask.

No, the netmask is the right one, as in all other PCs of the LAN.

Paul D.Smith wrote:
>>Perhaps you entered an incompatible netmask.
>
>
> Sure this PC is not clashing with one given the same IP address through
> DHCP?

No, I am sure, the IP I choose is a free one.

>
> Also, did you know that you can get DHCP to reserve a specific address for a
> specific machine (actually specific MAC address on the network card in that
> machine)? This can allow you to set all machines the "DHCP" but ensure that
> specific machines always get the same IP address.


No, I did not know (anyway I cannot find this feature in moy router).
But I do not think it could help, because for that notebook I need the
setting "Specify an IP address" and not "Obtain an IP address
automatically" because the notebook will be used in other LAN whitout
DHCP too.

Comments below.

Paul DS.

"Giobibo" <(E-Mail Removed)> wrote in message
news:do5s7j$pmj$(E-Mail Removed)...
> Paul D.Smith wrote:
> >>Perhaps you entered an incompatible netmask.
> >
> >
> > Sure this PC is not clashing with one given the same IP address through
> > DHCP?
>
> No, I am sure, the IP I choose is a free one.
>
> >
> > Also, did you know that you can get DHCP to reserve a specific address
for a
> > specific machine (actually specific MAC address on the network card in
that
> > machine)? This can allow you to set all machines the "DHCP" but ensure
that
> > specific machines always get the same IP address.
>
>
> No, I did not know (anyway I cannot find this feature in moy router).
> But I do not think it could help, because for that notebook I need the
> setting "Specify an IP address" and not "Obtain an IP address
> automatically" because the notebook will be used in other LAN whitout
> DHCP too.
>
>

Lets say your router assigned 192.168.0.X (quite common). What IP address
have you given the PC? If it is not a "192.168.0.X" style address, it
probably won't work because your router will look at the address and the
address mask (255.255.255.0 commonly) and then dump any packets that don't
match.

So you need to make sure that your static address matches the subnet of the
router. If this means that it must look like a DHCP address, then you
should both provide a static IP address and also ensure that your router
does not assign that address to another PC.

What is the netmask and IP address you are using, and if you request DHCP,
what IP address and netmask does the router assign? Knowing these might
help the NG readers help you further.

Paul DS.

Paul D.Smith wrote:

> What is the netmask and IP address you are using, and if you request DHCP,
> what IP address and netmask does the router assign? Knowing these might
> help the NG readers help you further.

Well, for this specific LAN I use the addresses 200.0.0.X and subnet
255.255.255.0.

The DHCP is so configured in order to assign the addresses in the range
200.0.0.100 - 200.0.0.255.

In this way I use the range 200.0.0.0 - 200.0.0.99 for all fixed IPs and
let the router to assign the rest in the range 100-255 (in this way I
get never conflicts). The router themself is at 200.0.0.200.

With this schema I have no problem with all other PCs in the LAN: they
all run fine (even if an old win95 PC with fixed IP). This Win98SE PC is
the only that does not work with fixed IP, I cannot find in its network
setting any specific difference against the other PCs of the LAN.

"Giobibo" <(E-Mail Removed)> wrote in message
news:do5rpv$pc7$(E-Mail Removed)...
> CJT wrote:
>
>> Perhaps you entered an incompatible netmask.
>
> No, the netmask is the right one, as in all other PCs of the LAN.
>

When using a specific IP address ..do you specify DNS and Gateway also ?

Haggis wrote:

>>>Perhaps you entered an incompatible netmask.
>>
>>No, the netmask is the right one, as in all other PCs of the LAN.
>>
>
>
> When using a specific IP address ..do you specify DNS and Gateway also ?

No, normally not, because in all other PCs I do not set DNS and Gateway
if do not need internet connection and they still work in the LAN.

For those PCs with specific IP where I need an internet connection I set
the gateway as the IP of the router and the two DNS addresses provided
by my internet provider.

Giobibo wrote:

> Haggis wrote:
>
>>>> Perhaps you entered an incompatible netmask.
>>>
>>>
>>> No, the netmask is the right one, as in all other PCs of the LAN.
>>>
>>
>>
>> When using a specific IP address ..do you specify DNS and Gateway also ?
>
>
> No, normally not, because in all other PCs I do not set DNS and Gateway
> if do not need internet connection and they still work in the LAN.
>
> For those PCs with specific IP where I need an internet connection I set
> the gateway as the IP of the router and the two DNS addresses provided
> by my internet provider.
>
>
From the information you have provided, it seems it should work.

Check that your router has the latest firmware. I suspect it is buggy.

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