Weird problem

Two pc's connected with crossover cable. DHCP works, the client gets an IP. But I cant ping the host from the client
or vice versa. No traceroutes or dns or anything works. But they are aware of each other, if I turn one off or change
speed or hostname the other one notices immediately.
Tried absolutely everything.




nick

nick wrote:
> Two pc's connected with crossover cable. DHCP works, the client gets an IP. But I cant ping the host from the client
> or vice versa. No traceroutes or dns or anything works. But they are aware of each other, if I turn one off or change
> speed or hostname the other one notices immediately.
> Tried absolutely everything.
>
>
You don't have software firewalls running on either of these machines do
you?

Also you say one gets an ip address, I assume this is from the dhcp
server on the other machine? The server ip and dhcp server ranges will
allow communications won't they? The ip address of the client is one
from the dhcp range and not an automatically allocated one by windows
which it may give it a dhcp server can’t be found?

When you say the other notices immediately what do you mean, an tcp/ip
error or just a link failure detected?

Andrew




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"Andrew Welham" <(E-Mail Removed)> wrote in message news:41f3f17a$0$16572$(E-Mail Removed)...
> nick wrote:
>> Two pc's connected with crossover cable. DHCP works, the client gets an IP. But I cant ping the host from the client
>> or vice versa. No traceroutes or dns or anything works. But they are aware of each other, if I turn one off or change
>> speed or hostname the other one notices immediately.
>> Tried absolutely everything.
>>
>>
> You don't have software firewalls running on either of these machines do you?
>
> Also you say one gets an ip address, I assume this is from the dhcp server on the other machine? The server ip and
> dhcp server ranges will allow communications won't they? The ip address of the client is one from the dhcp range and
> not an automatically allocated one by windows which it may give it a dhcp server can’t be found?
>
> When you say the other notices immediately what do you mean, an tcp/ip error or just a link failure detected?
>
> Andrew
>
>

No firewalls. The client gets the IP from the host via dhcp. Its in the 192.168.0.x range
so its not due to dhcp failure. When I boot one the other pc notices the LAN connection.
tcp/ip just isnt working, I cant ping either one from the other, or anything.

On Sun, 23 Jan 2005 03:26:37 +0000, nick wrote:

> Two pc's connected with crossover cable. DHCP works, the client gets an
> IP. But I cant ping the host from the client or vice versa. No traceroutes
> or dns or anything works. But they are aware of each other, if I turn one
> off or change speed or hostname the other one notices immediately. Tried
> absolutely everything.

Some network cards don't like to work back to back for some reason. I'ts
well worth inesting in a hub. Should cost less than 20 quid. You will also
be able to add more PC's to your network later.

GrahamW

nick wrote:
> "Andrew Welham" <(E-Mail Removed)> wrote in message news:41f3f17a$0$16572$(E-Mail Removed)...
>
>>nick wrote:
>>
>>>Two pc's connected with crossover cable. DHCP works, the client gets an IP. But I cant ping the host from the client
>>>or vice versa. No traceroutes or dns or anything works. But they are aware of each other, if I turn one off or change
>>>speed or hostname the other one notices immediately.
>>>Tried absolutely everything.
>>>
>>>
>>
>>You don't have software firewalls running on either of these machines do you?
>>
>>Also you say one gets an ip address, I assume this is from the dhcp server on the other machine? The server ip and
>>dhcp server ranges will allow communications won't they? The ip address of the client is one from the dhcp range and
>>not an automatically allocated one by windows which it may give it a dhcp server can’t be found?
>>
>>When you say the other notices immediately what do you mean, an tcp/ip error or just a link failure detected?
>>
>>Andrew
>>
>>
>
>
> No firewalls. The client gets the IP from the host via dhcp. Its in the 192.168.0.x range
> so its not due to dhcp failure. When I boot one the other pc notices the LAN connection.
> tcp/ip just isnt working, I cant ping either one from the other, or anything.
>
>
>
I assume from your email that both PCs are in the 192.168.0.x range, and
that one of the PC's is the dhcp server while the other is the client ?

Also that there is only one nic in each PC, and not other ip routable
interface i.e. modem pstn or adsl etc ? (if you have more ip routable
interfaces you need to check the routing)

Are you trying to ping via IP or hostname?

Can you ping the localhost on each PC i.e 127.0.0.1

If you are receiving via DHCP the IP address and the netmasks are also
correct I would guess 255.255.255.0, then there must be some IP
connectivity, i.e. the entire stack has not failed.

Do any other ip actions work?

Andrew

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To reply via email, first reverse the address below then replace the
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"GrahamW" <(E-Mail Removed)> wrote in message news(E-Mail Removed)...
> On Sun, 23 Jan 2005 03:26:37 +0000, nick wrote:
>
>> Two pc's connected with crossover cable. DHCP works, the client gets an
>> IP. But I cant ping the host from the client or vice versa. No traceroutes
>> or dns or anything works. But they are aware of each other, if I turn one
>> off or change speed or hostname the other one notices immediately. Tried
>> absolutely everything.
>
> Some network cards don't like to work back to back for some reason. I'ts
> well worth inesting in a hub. Should cost less than 20 quid. You will also
> be able to add more PC's to your network later.
>
> GrahamW
>

Maybe it'll come to that, but id rather get a router if im gonna have to buy another box.

"Andrew Welham" <(E-Mail Removed)> wrote in message news:41f4139f$0$19158$(E-Mail Removed)...
> nick wrote:
>> "Andrew Welham" <(E-Mail Removed)> wrote in message news:41f3f17a$0$16572$(E-Mail Removed)...
>>
>>>nick wrote:
>>>
>>>>Two pc's connected with crossover cable. DHCP works, the client gets an IP. But I cant ping the host from the client
>>>>or vice versa. No traceroutes or dns or anything works. But they are aware of each other, if I turn one off or
>>>>change speed or hostname the other one notices immediately.
>>>>Tried absolutely everything.
>>>>
>>>>
>>>
>>>You don't have software firewalls running on either of these machines do you?
>>>
>>>Also you say one gets an ip address, I assume this is from the dhcp server on the other machine? The server ip and
>>>dhcp server ranges will allow communications won't they? The ip address of the client is one from the dhcp range and
>>>not an automatically allocated one by windows which it may give it a dhcp server can’t be found?
>>>
>>>When you say the other notices immediately what do you mean, an tcp/ip error or just a link failure detected?
>>>
>>>Andrew
>>>
>>>
>>
>>
>> No firewalls. The client gets the IP from the host via dhcp. Its in the 192.168.0.x range
>> so its not due to dhcp failure. When I boot one the other pc notices the LAN connection.
>> tcp/ip just isnt working, I cant ping either one from the other, or anything.
>>
>>
>>
> I assume from your email that both PCs are in the 192.168.0.x range, and that one of the PC's is the dhcp server while
> the other is the client ?
>
> Also that there is only one nic in each PC, and not other ip routable interface i.e. modem pstn or adsl etc ? (if you
> have more ip routable interfaces you need to check the routing)
>
> Are you trying to ping via IP or hostname?
>
> Can you ping the localhost on each PC i.e 127.0.0.1
>
> If you are receiving via DHCP the IP address and the netmasks are also correct I would guess 255.255.255.0, then there
> must be some IP connectivity, i.e. the entire stack has not failed.
>
> Do any other ip actions work?
>
> Andrew
>
> --
> To reply via email, first reverse the address below then replace the (at) with @ and the (dot) with .
> moc(tod)xepip(tod)lsd(ta)spuorgswen_werdna


Its definitely a cable or hardware fault. Ran tcpdump on both pc's, and its very intermittent.

what operating systems are you using?

Windows 98 / ME aren't that great at using DHCP.
Windows XP / 2000 will remember the IP address it had at last login, so as
long as it's connected at least once, it will probably keep the same IP
address.

--
Regards
Roger Mayne

Helpdesq Partnership T/A Absolute Computer Services
Leith Lodge
Horsham Road
Beare Green
Surrey
RH5 4PF

Tel: 07000 560793
Fax: 01306 710112
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"nick" <(E-Mail Removed)> wrote in message
news:41f41c7c$0$70396$(E-Mail Removed)...
>
> "Andrew Welham" <(E-Mail Removed)> wrote in message
news:41f4139f$0$19158$(E-Mail Removed)...
> > nick wrote:
> >> "Andrew Welham" <(E-Mail Removed)> wrote in message
news:41f3f17a$0$16572$(E-Mail Removed)...
> >>
> >>>nick wrote:
> >>>
> >>>>Two pc's connected with crossover cable. DHCP works, the client gets
an IP. But I cant ping the host from the client
> >>>>or vice versa. No traceroutes or dns or anything works. But they are
aware of each other, if I turn one off or
> >>>>change speed or hostname the other one notices immediately.
> >>>>Tried absolutely everything.
> >>>>
> >>>>
> >>>
> >>>You don't have software firewalls running on either of these machines
do you?
> >>>
> >>>Also you say one gets an ip address, I assume this is from the dhcp
server on the other machine? The server ip and
> >>>dhcp server ranges will allow communications won't they? The ip
address of the client is one from the dhcp range and
> >>>not an automatically allocated one by windows which it may give it a
dhcp server can't be found?
> >>>
> >>>When you say the other notices immediately what do you mean, an tcp/ip
error or just a link failure detected?
> >>>
> >>>Andrew
> >>>
> >>>
> >>
> >>
> >> No firewalls. The client gets the IP from the host via dhcp. Its in the
192.168.0.x range
> >> so its not due to dhcp failure. When I boot one the other pc notices
the LAN connection.
> >> tcp/ip just isnt working, I cant ping either one from the other, or
anything.
> >>
> >>
> >>
> > I assume from your email that both PCs are in the 192.168.0.x range, and
that one of the PC's is the dhcp server while
> > the other is the client ?
> >
> > Also that there is only one nic in each PC, and not other ip routable
interface i.e. modem pstn or adsl etc ? (if you
> > have more ip routable interfaces you need to check the routing)
> >
> > Are you trying to ping via IP or hostname?
> >
> > Can you ping the localhost on each PC i.e 127.0.0.1
> >
> > If you are receiving via DHCP the IP address and the netmasks are also
correct I would guess 255.255.255.0, then there
> > must be some IP connectivity, i.e. the entire stack has not failed.
> >
> > Do any other ip actions work?
> >
> > Andrew
> >
> > --
> > To reply via email, first reverse the address below then replace the
(at) with @ and the (dot) with .
> > moc(tod)xepip(tod)lsd(ta)spuorgswen_werdna
>
>
> Its definitely a cable or hardware fault. Ran tcpdump on both pc's, and
its very intermittent.
>
>

before you do that, check the speed/duplex settings on both NICs.
they're usually defaulted to "auto" and this sometimes causes odd
intermittent issues.
to get around this, try explicitly setting both to the same, e.g.
100mbit full duplex and report back.

ric

tried this, made no difference.

"ric" <(E-Mail Removed)> wrote in message news:(E-Mail Removed) oups.com...
> before you do that, check the speed/duplex settings on both NICs.
> they're usually defaulted to "auto" and this sometimes causes odd
> intermittent issues.
> to get around this, try explicitly setting both to the same, e.g.
> 100mbit full duplex and report back.
>
> ric
>