Two different Subnet Masks required?

[Guest]

We have a 9 person network with Windows 2000 Server. The clients are XP. Our
internet is through ADSL. We're having a problem where certain workstations
lost connectiviity to server but had internet access. I did a ipconfig and
the only difference between the workstations that are connected and those
that aren't is the subnet mask. On computers not connecting it is
255.255.247. Others are 255.255.255. I manually adjusted TCP/IP to change it
to 255.255.255 and can then connect to server but lose connection to
internet. Ipconfig on server shows subnet mask as 255.255.247. Is there
someting else I can try or some reference.
Thanks

 

[Lanwench [MVP - Exchange]]

In

We have a 9 person network with Windows 2000 Server.

A domain, or a workgroup?

The clients are
XP. Our internet is through ADSL.

Connected to your network how / via what? You should be using even a cheap
router/gateway appliance (although I'd recommend something more robust to
protect your network at the permiter) - have it do NAT. Then on your LAN you
should be using a private/non-routable IP network (192.168.0.0, 172.16.1.0,
etc....)....and your own server can do DHCP.

We're having a problem where
certain workstations lost connectiviity to server but had internet
access. I did a ipconfig and the only difference between the
workstations that are connected and those that aren't is the subnet
mask. On computers not connecting it is 255.255.247. Others are
255.255.255. I manually adjusted TCP/IP to change it to 255.255.255
and can then connect to server but lose connection to internet.
Ipconfig on server shows subnet mask as 255.255.247.

Something is funky here but I'd want to know more about your
setup....including how your workstations get their IP addresses in the first
place.

 

[John Wunderlich]

We have a 9 person network with Windows 2000 Server. The clients
are XP. Our internet is through ADSL. We're having a problem where
certain workstations lost connectiviity to server but had internet
access. I did a ipconfig and the only difference between the
workstations that are connected and those that aren't is the
subnet mask. On computers not connecting it is 255.255.247. Others
are 255.255.255. I manually adjusted TCP/IP to change it to
255.255.255 and can then connect to server but lose connection to
internet. Ipconfig on server shows subnet mask as 255.255.247. Is
there someting else I can try or some reference.
Thanks

These subnet masks do not make sense.
For a 9-person subnet, the subnet mask should be one of the following:
255.255.255.0 255.255.255.128 255.255.255.192 255.255.255.224 or
255.255.255.240

HTH,
John

 

[Guest]

Its a domain.
We have an Intel Switch
The IP network is 192.168.1.???
The workstations get their IP address from the server. They were
Automatically obtaining IP address.
Can the switch mess things up? We had noticed that one workstation
completely lost all connection to server and internet. We rerouted wires on
switch (we have a few empty offices and slots on switch) and it seems to
work.
Thanks

 

[Kurt]

247 is not a valid number for a subnet mask. Also, there are 4 octets, not 3
(255.255.255 is 3/4 of a subnet mask). Subnet mask octets can be 0, 128,
192, 224, 240, 248, or 252. If referring to the last octet (the rightmost),
(i.e. 255.255.255.X), the number of host-assignable IP addresses per subnet
for each are:\

..0 254
..128 126
..192 62
..224 30
..240 14
..248 6
..252 2

Subnet masks must be the same for all Windows workstations if you want the
network browser to work. Otherwise, the IP addresses must all be within the
range of the most restrictive subnet mask for computers to communicate on
the LAN. The router also must have a subnet mask at least as wide as the
workstations.

A switch won't be a problem for a TCP/IP network unless it is configured for
"subnet VLANs", where it will look at the IP address and assign the packet
to a VLAN based on it's IP subnet.