two computer network, 100% packet loss

two computer network, 100% packet loss

Post by Christophe » Thu, 25 Mar 1999 04:00:00



Hello, I am trying to setup a mini network with two computers.  I have
read the instructions from NET-3 and ORA's TCP/IP but I still can't
get the computers talking.  I am using two DEC ethernet cards (DE200,
and DE205) that appear to be working with out conflicts.  They
attached with thin net cable which is terminated at both ends.  

I used ifconfig on the first and set the address to eth0 to 172.16.1.3
with netmask 255.255.0.0. The other computer is eth0 172.16.1.2.

On the first machine route -n gives
Dest    Gateway Genmask Flags   ...     Iface
172.16.1.2    0.0.0.0     255.255.255.255 UH                      eth0
127.0.0.0      0.0.0.0  255.0.0.0                U                  lo

On the other:
Dest    Gateway Genmask Flags   ...     Iface
172.16.1.3    0.0.0.0     255.255.255.255 UH                      eth0
127.0.0.0      0.0.0.0  255.0.0.0                U                  lo

When I ping from either machine with
        ping 172.16.1.2 or ping 172.16.1.3  
I get the following message:
PING 172.16.1.2 : 56 data bytes

After ctrl-c
--- 172.16.1.2 ping statistics ---
7 packets transmitted, 0 packets recieved, 100% packet loss

Both machines give the same messages.

Please give me some ideas as to what could be causing the problem.
Thanks.

 
 
 

two computer network, 100% packet loss

Post by William R. Matti » Fri, 26 Mar 1999 04:00:00



> Hello, I am trying to setup a mini network with two computers.  I have
> read the instructions from NET-3 and ORA's TCP/IP but I still can't
> get the computers talking.  I am using two DEC ethernet cards (DE200,
> and DE205) that appear to be working with out conflicts.  They
> attached with thin net cable which is terminated at both ends.

> I used ifconfig on the first and set the address to eth0 to 172.16.1.3
> with netmask 255.255.0.0. The other computer is eth0 172.16.1.2.

> On the first machine route -n gives
> Dest    Gateway Genmask Flags   ...     Iface
> 172.16.1.2    0.0.0.0     255.255.255.255 UH                      eth0
> 127.0.0.0      0.0.0.0  255.0.0.0                U                  lo

> On the other:
> Dest    Gateway Genmask Flags   ...     Iface
> 172.16.1.3    0.0.0.0     255.255.255.255 UH                      eth0
> 127.0.0.0      0.0.0.0  255.0.0.0                U                  lo

> When I ping from either machine with
>         ping 172.16.1.2 or ping 172.16.1.3
> I get the following message:
> PING 172.16.1.2 : 56 data bytes

> After ctrl-c
> --- 172.16.1.2 ping statistics ---
> 7 packets transmitted, 0 packets recieved, 100% packet loss

> Both machines give the same messages.

> Please give me some ideas as to what could be causing the problem.
> Thanks.

It could be that these cards are trying to use the TP port on the NIC's
instead of the BNC connector ? If they have both connectors on the NIC
this is where I would check first.

Regards
Bill

--
William R. Mattil       | Fred Astaire wasn't so great.

(972) 399-4106          | and... in high heels.

 
 
 

two computer network, 100% packet loss

Post by Frank Ha » Sat, 27 Mar 1999 04:00:00



>Hello, I am trying to setup a mini network with two computers.  I have
>read the instructions from NET-3 and ORA's TCP/IP but I still can't
>get the computers talking.  I am using two DEC ethernet cards (DE200,
>and DE205) that appear to be working with out conflicts.  They
>attached with thin net cable which is terminated at both ends.  

>I used ifconfig on the first and set the address to eth0 to 172.16.1.3
>with netmask 255.255.0.0. The other computer is eth0 172.16.1.2.

>On the first machine route -n gives
>Dest        Gateway Genmask Flags   ...     Iface
>172.16.1.2    0.0.0.0     255.255.255.255 UH                      eth0
>127.0.0.0      0.0.0.0  255.0.0.0                U                  lo

>On the other:
>Dest        Gateway Genmask Flags   ...     Iface
>172.16.1.3    0.0.0.0     255.255.255.255 UH                      eth0
>127.0.0.0      0.0.0.0  255.0.0.0                U                  lo

>When I ping from either machine with
>    ping 172.16.1.2 or ping 172.16.1.3  
>I get the following message:
>PING 172.16.1.2 : 56 data bytes

>After ctrl-c
>--- 172.16.1.2 ping statistics ---
>7 packets transmitted, 0 packets recieved, 100% packet loss

>Both machines give the same messages.

You might try reading through the Network Administrators Guide.  It
is usually on the CD.  At least it has been on the Slackware CD's I
have purchased in the past.  You can also purchase a hard copy.  It
might be published by O'Reilly, not sure.

Is the 172.XXX.XXX.XXX series of numbers valid for private use?  I
can't remember.  I use 192.168.100.XX numbers.

I have a Slackware system.  All of my networking stuff is setup in
the /etc/rc.d/rc.inet1 file.  This may be different on a Redhat system.

Here is a copy of that files contents:

=================cut-here=================================
#! /bin/sh
#
# rc.inet1      This shell script boots up the base INET system.
#

#

HOSTNAME=`cat /etc/HOSTNAME`

# Attach the loopback device.
/sbin/ifconfig lo 127.0.0.1
/sbin/route add -net 127.0.0.0 netmask 255.0.0.0 lo

# IF YOU HAVE AN ETHERNET CONNECTION, use these lines below to configure the
# eth0 interface. If you're only using loopback or SLIP, don't include the
# rest of the lines in this file.

# Edit for your setup.
IPADDR="192.168.100.10" # REPLACE with YOUR IP address!
NETMASK="255.255.255.0" # REPLACE with YOUR netmask!
NETWORK="192.168.100.0" # REPLACE with YOUR network address!
BROADCAST="192.168.100.255"     # REPLACE with YOUR broadcast address, if you
                        # have one. If not, leave blank and edit below.
#GATEWAY=""     # REPLACE with YOUR gateway address!

# Uncomment the line below to initialize the ethernet device.
/sbin/ifconfig eth0 ${IPADDR} broadcast ${BROADCAST} netmask ${NETMASK}

# Uncomment these to set up your IP routing table.
/sbin/route add -net ${NETWORK} netmask ${NETMASK} eth0

# End of rc.inet1
==================The End==========================================

I don't know if this will help or not but I it will give you something
to compare to.

Also, have you set up /etc/hosts files with the IP addresses for both
machines in it on both of your machines?

Of course, I'm assuming that you are confident that there are no
problems with network cards, cables, etc.

--
Frank Hahn

 
 
 

two computer network, 100% packet loss

Post by miguel cervante » Sat, 27 Mar 1999 04:00:00


[ text1.txt 1K ]

Quote:>>>>>>>>>>>>>>>>>> Original Message <<<<<<<<<<<<<<<<<<


regarding Re: two computer network, 100% packet loss:

Quote:> >On the first machine route -n gives
> >Dest Gateway Genmask Flags   ...     Iface
> >172.16.1.2    0.0.0.0     255.255.255.255 UH                      
eth0
> >127.0.0.0      0.0.0.0  255.0.0.0                U                  
lo

> >On the other:
> >Dest Gateway Genmask Flags   ...     Iface
> >172.16.1.3    0.0.0.0     255.255.255.255 UH                      
eth0
> >127.0.0.0      0.0.0.0  255.0.0.0                U                  

lo

Quote:> Is the 172.XXX.XXX.XXX series of numbers valid for private use?  I
> can't remember.  I use 192.168.100.XX numbers.

I igree 172.x.x.x???   i use 10.0.0.0 and my routing table for 3 boxes
is

127.0.0.0               *       255.0.0.0
10.0.0.0                *       255.255.255.0

since all my boxes are in the same network there will be no routing
needed... I think
and i don't have a default gateway setup neither so i guess my linux
box will be the default route. When i connect to the internet is a
diferent story.....!!!

 
 
 

two computer network, 100% packet loss

Post by mist » Sat, 27 Mar 1999 04:00:00



Quote:>Hello, I am trying to setup a mini network with two computers.  I have
>read the instructions from NET-3 and ORA's TCP/IP but I still can't
>get the computers talking.  I am using two DEC ethernet cards (DE200,
>and DE205) that appear to be working with out conflicts.  They
>attached with thin net cable which is terminated at both ends.  

>I used ifconfig on the first and set the address to eth0 to 172.16.1.3
>with netmask 255.255.0.0. The other computer is eth0 172.16.1.2.

               ^^^^^^^^^^

This should really be 255.255.255.0 for such a small network, or it's
wasteful and inefficient. And you should really use a net part like
192.168.1.* or something else more private, in case you link them to the
'net later.

Quote:

>On the first machine route -n gives
>Dest   Gateway Genmask Flags   ...     Iface
>172.16.1.2    0.0.0.0     255.255.255.255 UH                      eth0
>127.0.0.0      0.0.0.0  255.0.0.0                U                  lo

I'm not sure those look quite right..  Shouldn't there be a 0 in the
last part of the mask for the 172... bit?  and my mask for the lo
interface looks like 255.255.255.0 though that is unrelated..

<snip>

I'd try taking the thing down and setting it back up again slightly
differently.  Try

ifconfig eth0 down

on both machines then

ifconfig 192.168.1.2 netmask 255.255.255.0 broadcast 192.168.1.255 eth0
up

^^ the above should be one line incase it wraps to two.  Also it might
be slightly syntax incorrect, as I'm trying to do it from memory..

And on the other machine

ifconfig 192.168.1.3 netmask 255.255.255.0 broadcast 192.168.1.255 eth0
up

Again, the above should be one line.

Also check that the IRQs etc are correct for the cards.

Then, for each machine -

route add -net 192.168.1.0

And possibly (I think you could do without this)

route add default gw 192.168.1.[machine number]

Oh, and of course make sure that you don't have any firewall rules in
place that could be interfering with the pings...

HTH
--
Mist.

 
 
 

two computer network, 100% packet loss

Post by M. Buchenried » Sun, 28 Mar 1999 04:00:00




>>Hello, I am trying to setup a mini network with two computers.  I have
>>read the instructions from NET-3 and ORA's TCP/IP but I still can't
>>get the computers talking.  I am using two DEC ethernet cards (DE200,
>>and DE205) that appear to be working with out conflicts.  They
>>attached with thin net cable which is terminated at both ends.  

Good.

Quote:

>>I used ifconfig on the first and set the address to eth0 to 172.16.1.3
>>with netmask 255.255.0.0. The other computer is eth0 172.16.1.2.
>               ^^^^^^^^^^
>This should really be 255.255.255.0 for such a small network, or it's
>wasteful and inefficient. And you should really use a net part like
>192.168.1.* or something else more private, in case you link them to the
>'net later.

Well, inefficient, yes, in a way. You don't need a class B network for
2 machines . However, this is a perfectly valid IP address for private
networks. See RFC 1597 .

Quote:

>>On the first machine route -n gives
>>Dest   Gateway Genmask Flags   ...     Iface
>>172.16.1.2    0.0.0.0     255.255.255.255 UH                      eth0
>>127.0.0.0      0.0.0.0  255.0.0.0                U                  lo

>I'm not sure those look quite right..  Shouldn't there be a 0 in the
>last part of the mask for the 172... bit?  

The route _itself_ is correct. What's missing is the route to the
network, though. The above listed route is a route to the host at
172.16.1.2 , not a route to the 172.16.1.0 network . The command
should be

route add -net 172.16.1.0 eth0

otherwise only the 172.16.1.2 address is reachable via the eth0
interface (and not 172.16.1.1 or all others).

Quote:>and my mask for the lo
>interface looks like 255.255.255.0 though that is unrelated..

[...]

Wrong (though irrelevant) . 127.0.0.0 must have a 255.0.0.0 netmask.

Michael
--

          Lumber Cartel Unit #456 (TINLC) & Official Netscum
    Note: If you want me to send you email, don't munge your address.