moocowjuice-ga... I asked a question about not being able to get
online. Question is here:
http://answers.google.com/answers/threadview?id=392703 and I was
looking over what you wrote and you said that the IP address was not
valid because it had 255 in it. Well I checked again today, I ran
IPCONFIG and came up with another IP address with 255 in that you said
was a broadcast IP address. His ISP (Lightlink) was saying that his
computer was showing a ton of connections on it, could this be because
of his IP address, how can I fix this for him???

Here's what I got when I ran IPCONFIG today:
IP Add: 10.255.101.3
Subnet Mask: 255.255.255.0
Default Gateway: 10.255.101.1

His roomates are: 
IP Address: 192.168.101.223
Subnet Mask: 255.255.0
Default Gateway: 192.168.101.1

When I ping the loopback address everything is fine as it is when I
ping the IP address of his computer.  But when I try to ping his
roommates computer or his default gateway, it's telling it times out.
All 4 tries are lost.

I tried flushing the ARP Cache and still no internet connection. Can
you help me out??

---

Clarification of Question by topazljf-ga on 28 Sep 2004 15:43 PDT

The subnest mask for the computer that doesn't (according to IPCONFIG)
is definitely 255.255.255.0 as it is with his roommates computer, so
maybe that is the problem?

The IP Address is assigned by the ISP. And as for the malware, I ran
spybot, hijack this (and had the log analyzed til it was clean) and
also adaware.  I also ran AVG and Nortons for virus protection and
it's saying that it is clean. Any other suggestions?

I don't know if it's the problem, but the subnet mask is incorrect.
For the 10.255.101.3 address given the expected mask would be
255.255.0.0. The other subnet mask is also incorrect, it should be
255.255.255.0.

I would agree with the message in the other thread that it's unusual
to see 255 used I think how that would be handled is router-dependent
- some may handle them and some may not. Is this an ISP assigned
address or are you using DHCP? Presumably the ISP knows what they are
doing and wouldn't provide an invalid address for their equipment.

Too many connections makes me suspect that you still have malware
running that is trying to phone home.

Open the command-prompt (if you're using Windows), type in:

ipconfig/release - to release your current ip address

and

ipconfig/renew - to renew your ip address

Releasing and renewing your ip address might help.

255 should not be thought of as always being the boadcast ID for a
given network. if you have a class of IPs subnetted down, you could
easily have a different broadcast ID and network ID other then .0 and
.255 respectively.

Here's a simple example of being able to use 255 in an IP.

if you have the default class B address of 132.120.0.0/16 and you
subnet it to a class C 132.120.0.0/22 you get 64 subnets with 1024 IPs
per subnet. so in the first subnet you have this range.

132.120.0.0/22 - 132.120.3.255/22

with the very first address being your Network ID and the vary last
being your broadcast ID.

now think about all the IPs in that range... would 132.120.2.255/22 be
in there? and if so, would that be a broadcast ID?

the answer is yes it is in the range as a valid IP address, and it is
not the  broadcast ID. We have already established the broadcast ID of
132.120.3.255/22.

In your case, the subnet mask will show you where the host portion and
network portion of the IP address are. The 255 in the second octet
sits in the network portion of the IP address and therefore and easily
be dismissed as the broadcast ID.

Conclusion: The IP addresses are/should be fine. However, you may not
be able to ping to your roomates computer do to an incorrect router
config between the two. Always remember you need a router to talk
accross networks, and thats exactly what you are trying to do when
going from the 10.255.101.0/24 network to the 192.168.101.0./24
network. (both of which are prvate IPs [meaning non routable on the
internet])