Network unreachable; routing problems?

Network unreachable; routing problems?

Post by Vincent Zweij » Sat, 26 Sep 1998 04:00:00





||  I am running RedHat 4.2 on a P5/60 machine with a NE2000 clone network
||  card.  A few days ago I moved the machine to a different subnet, and had to
||  reconfigure the IP settings.  I changed the settings and the network was
||  unreachable.  The only pings returned were through the local loopback
||  (127.0.0.1), the broadcast (xxx.xxx.xxx.255) and the IP address of the
||  machine (xxx.xxx.xxx.xxx).  No pings from anywhere else, even the local
||  subnet, were returned.      However, /proc/net/dev shows that packets are
||  transmitted, but not received over eth0.

If all that information is correct, then it must be working.  Since it's
not working, the information cannot be correct.

Show the information instead of drawing your own conclusions.

By the way, make sure your gateway is right.

||  The information in ifconfig looked normal, the settings were all correct.
||  But when I tried route to list the routing table, a funny thing happened.
||  The first two routes, the loopback and the route to xxx.xxx.xxx.0, showed
||  up, and when the default route was supposed to show up, there was no more
||  output; to return to a prompt I had to do ^C.  Yet /proc/net/route shows
||  the default route, and the numbers seem OK, including the gateway IP.  Is
||  it correct for the netmask under the default route to be listed as 0.0.0.0?
||  What could be causing this problem?  I am certain of the IP numbers, since
||  another machine works using those same numbers...

Patience is a virtue too.

The route command want to do a reverse name lookup on your default
gateway.  This is not in your hosts file.  Therefore, it goes to ask
your nameserver.  However, no response comes back.  You've probably set
it wrong.

After a timeout (20 seconds, a minute, I'm not sure) it will give up
and just print the numeric gateway address.

You can also use the -n option to get numeric results only.

Oh by the way, who are you?

Bye.                                                           Vincent.
--

<http://www.xs4all.nl/~zweije/>      | don't read, does anybody get burnt?"
[Xhost should be taken out and shot] |            -- Paul Tomblin on a.s.r.

 
 
 

1. rtnetlink: network unreachable for Routing for multiple uplinks using ip route add

Dear all,
after playing around and having the same problems on all linux
versions I have at hand and not finding a solution in the net I ask
for your help.

Problem: Want to set up a router with multiple uplinks to the
internet.
Checked documentation at several places, but all examples given will
not work!
Always get rtnetlink: network is unreachable.

Have tried this with IPCop 1.4.5, SUSE Prof. 9.1 same effect.

OK now the details:

For ISP 1 (all IP addresses not the real ones!)
eth0:      10.138.233.227
NETMASK:   255.255.255.240
GW:        10.138.233.226

For ISP2
eth1       10.51.238.226
NETMASK:   255.255.255.240
GW:        10.51.238.226

/etc/rt_tables: (added at end)
200 T1
201 T2

Routing table empty but loopback device when I start:
ip route add 10.138.233.224/28 dev eth0 src 10.138.233.227 table T1
ip route add default via 10.138.233.226 table T1
Error Message: rtnetlink: network is unreachable

ip route add 10.51.238.224/28 dev eth1 src 10.51.238.226 table T2
ip route add default via 10.51.238.225 table T2
Error Message: rtnetlink: network is unreachable

If I use the commands without the table T1/T2 I am able to set the
route. But later it doesn't work.
I took the commands from
   Linux Advanced Routing & Traffic Control HOWTO
   Chapter 4.2
And crosschecked with
    Redundant Internet Connections Using Linux from
    http://www.samag.com/documents/s=1824/sam0201h/0201h.htm

Same effect.
Kernel on Suse9.1:  2.6.4-52
Kernel on IPCop:    2.4.29

Kernel configured with:
    CONFIG_IP_ADVANCED_ROUTER=y
    CONFIG_IP_MULTIPLE_TABLES=y
    CONFIG_IP_ROUTE_MULTIPATH=y

ip version:
    Suse:  iproute2-ss020116
    ipcop: iproute2-ss010824

Any clues?

Thanks in advance
Joerg

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