Local Network Problem
Nils Kassube
kassube at gmx.net
Wed Aug 29 07:15:00 UTC 2007
Don Henson wrote:
> Eberhard Roloff wrote:
> > Don Henson wrote:
> >> To make a long background story short...
> >>
> >> In restoring from a major system crash, I ended up with a
> >> server/workstation, a workstation, and a laptop (wifi) that should
> >> be talking to each other over Ethernet. The laptop will not respond
> >> to a ping from anybody and the other two will respond to each
> >> other's pings if I use the domain address. They will not respond if
> >> I ping the corresponding IP address. This seems backwards to me but
> >> that's the way it is. At one point, I had all three machines talking
> >> but after rebooting all three, the problem returned. I've been
> >> working on this for a couple of days and now I find myself
> >> thoroughly confused. I have no idea which files and logs might be
> >> useful. If you are interested in helping, let me know what data you
> >> need and I'll post it forthwith. I'd really appreciate a little help
> >> on this one.
> >>
> >> Don Henson
> >
> > on each one:
> >
> > ifconfig eth0
> > cat /etc/hosts
> >
> > then: Do you use a dhcp server for your machines? (For example, your
> > router could be acting as such a server)
> >
> > do you use a firewall on all your machines or on specific machines?
> >
> > What does a packet sniffer, ex. ethereal show on your laptop, when
> > you try to ping it from another machine.
> >
> > If you are working with fixed ip addresses, what happes if you
> > connect only two machines via a crossover cable , i.e. leave out your
> > swith and anthing else in between.
> >
> > kind regards
> > Eberhard
>
> Per your request...
>
> For Earth-svr
> dhenson at Earth-svr:~$ ifconfig
> eth0 Link encap:Ethernet HWaddr 00:07:E9:9C:26:0B
> inet addr:192.168.1.51 Bcast:192.168.1.255
>
> dhenson at Earth-svr:~$ cat /etc/hosts
> # 127.0.0.1 localhost
Please uncomment this entry, although it seems to be unrelated to your
problems.
> 192.168.1.51 Earth-svr.site Earth-svr localhost
Localhost should be 127.0.0.1 not the address of an external interface. It
may work, but I think it is quite unusual.
> 192.168.1.52 Venus-ws.site Venus-ws
> 192.168.1.53 Mars-laptop.site Mars-laptop
>
> For Venus-ws
>
> jhenson at Venus-desktop:~$ ifconfig
> eth0 Link encap:Ethernet HWaddr 00:15:F2:5B:9B:10
> inet addr:192.168.1.52 Bcast:192.168.1.255
>
> jhenson at Venus-desktop:~$ cat /etc/hosts
> 127.0.0.1 localhost
> 192.168.1.51 Earth-svr.site Earth-svr
> 192.168.1.52 Venus-ws.site Venus-ws
> 192.168.1.53 Mars-laptop.site Mars-laptop
>
> For Mars-laptop
>
> dhenson at Mars-laptop:~$ ifconfig
> eth0 Link encap:Ethernet HWaddr 00:19:B9:76:09:3C
> inet addr:192.168.1.53 Bcast:192.168.1.255
>
> wlan0 Link encap:Ethernet HWaddr 00:19:7E:62:59:16
> inet addr:192.168.1.53 Bcast:192.168.1.255
Don't use two interfaces with the same IP address. That can't work. Please
note: An IP address defines an interface, not a machine. Probably this is
the reason why your laptop can't talk to anybody.
> dhenson at Mars-laptop:~$ cat /etc/hosts
> 127.0.0.1 localhost
> 192.168.1.51 Earth-svr.site Earth-svr
> 192.168.1.52 Venus-ws.site Venus-ws
> 192.168.1.53 Mars-laptop.site Mars-laptop.site
>
> The original install used DHCP but I am tryng to switch to static.
>
> My Linksys router/switch has a firewall. I use that and my machines
> have their firewalls turned off.
I don't see an entry for your router in any of your /etc/hosts files. You
should add a line
192.168.1.1 router.site router
to each of the files (I assume it has the address 192.168.1.1). Otherwise
you can't talk to the internet.
What is the output of the route command on your machines? It should look
like this:
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
192.168.1.0 * 255.255.255.0 U 0 0 0 eth0
default router.site 0.0.0.0 UG 0 0 0 eth0
The first line defines the local network, so you can talk to the other
local machines. These machines can be reached directly without a gateway.
The second line defines the rest of the world. To reach any non-local
machine the data should be sent to the gateway router.site.
BTW: Why don't you want to use DHCP? It can make life so much easier. If
you just don't want to use the built-in DHCP server of the router you
could install a DHCP server e.g. on your Earth-svr machine.
Nils
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