[4597] in linux-net channel archive
Subnetting troubles on linux 2.0.20
daemon@ATHENA.MIT.EDU (Janice McCarthy)
Mon Sep 30 16:24:49 1996
Date: Mon, 30 Sep 1996 12:27:39 -0400 (EDT)
From: Janice McCarthy <janice@acpub.duke.edu>
To: linux-net@vger.rutgers.edu
> > Here is the problem:
> > I want to add a route to the 172.16.2.0 network from a machine on
> > the 172.16.1.0 network. I type:
> >
> > route add -net 172.16.2.0 gw 172.16.1.3 dev eth1
> >
> > (eth1 is the 100Mb adapter)
> >
> > I get the following error:
> > SIOCADDRT: Invalid Argument.
Ok. I have gotten a little bit further... I can add the route properly
as long as I explicitly set the netmask in the route command. Fine. All
the routing tables look good:
A machine on FastNet(100Mb subnet):
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
172.16.1.0 0.0.0.0 255.255.255.0 U 0 0 3 eth1
172.16.2.0 172.16.1.3 255.255.255.0 UG 1 0 0 eth1
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 1 lo
lo Link encap:Local Loopback
inet addr:127.0.0.1 Bcast:127.255.255.255 Mask:255.0.0.0
UP BROADCAST LOOPBACK RUNNING MTU:7168 Metric:1
RX packets:12 errors:0 dropped:0 overruns:0
TX packets:12 errors:0 dropped:0 overruns:0
eth1 Link encap:10Mbps Ethernet HWaddr 00:00:C0:34:39:DC
inet addr:172.16.1.5 Bcast:172.16.1.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:3925 errors:0 dropped:0 overruns:0
TX packets:675 errors:1 dropped:0 overruns:0
Interrupt:15 Base address:0xb000
A machine on HubA (10Mb subnet):
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
172.16.2.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
172.16.1.0 172.16.2.3 255.255.255.0 UG 1 0 0 eth0
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 1 lo
lo Link encap:Local Loopback
inet addr:127.0.0.1 Bcast:127.255.255.255 Mask:255.0.0.0
UP BROADCAST LOOPBACK RUNNING MTU:7168 Metric:1
RX packets:12 errors:0 dropped:0 overruns:0
TX packets:12 errors:0 dropped:0 overruns:0
eth0 Link encap:10Mbps Ethernet HWaddr 08:00:2B:E2:C9:96
inet addr:172.16.2.11 Bcast:172.16.2.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:31 errors:0 dropped:0 overruns:0
TX packets:0 errors:0 dropped:0 overruns:0
Interrupt:10 Base address:0xb000
The Gateway:
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
172.16.2.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
172.16.1.0 0.0.0.0 255.255.255.0 U 0 0 3 eth1
127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo
lo Link encap:Local Loopback
inet addr:127.0.0.1 Bcast:127.255.255.255 Mask:255.0.0.0
UP BROADCAST LOOPBACK RUNNING MTU:7168 Metric:1
RX packets:30 errors:0 dropped:0 overruns:0
TX packets:30 errors:0 dropped:0 overruns:0
eth0 Link encap:10Mbps Ethernet HWaddr 08:00:2B:E4:03:B3
inet addr:172.16.2.3 Bcast:172.16.2.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:13 errors:0 dropped:0 overruns:0
TX packets:13 errors:0 dropped:0 overruns:0
Interrupt:10 Base address:0xb400
eth1 Link encap:10Mbps Ethernet HWaddr 00:00:C0:37:39:DC
inet addr:172.16.1.3 Bcast:172.16.1.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:2236 errors:0 dropped:0 overruns:0
TX packets:2189 errors:1 dropped:0 overruns:0
Interrupt:15 Base address:0xb000
Now, I can ping through the gateway (i.e. from a machine on HubA, to a
machine on FastNet) with no problem. But if I ping between any two
machines on the same physical network, I get DUP! messages... in fact,
each packet is duplicated 3 times.
PING drylab2.FastNet (172.16.1.2): 56 data bytes
64 bytes from 172.16.1.2: icmp_seq=0 ttl=64 time=9.7 ms
64 bytes from 172.16.1.2: icmp_seq=0 ttl=63 time=9.7 ms (DUP!)
64 bytes from 172.16.1.2: icmp_seq=0 ttl=64 time=19.5 ms (DUP!)
64 bytes from 172.16.1.2: icmp_seq=0 ttl=63 time=19.5 ms (DUP!)
64 bytes from 172.16.1.2: icmp_seq=1 ttl=64 time=0.0 ms
64 bytes from 172.16.1.2: icmp_seq=1 ttl=63 time=0.0 ms (DUP!)
64 bytes from 172.16.1.2: icmp_seq=1 ttl=64 time=0.0 ms (DUP!)
64 bytes from 172.16.1.2: icmp_seq=1 ttl=63 time=9.7 ms (DUP!)
64 bytes from 172.16.1.2: icmp_seq=2 ttl=64 time=0.0 ms
64 bytes from 172.16.1.2: icmp_seq=2 ttl=63 time=0.0 ms (DUP!)
64 bytes from 172.16.1.2: icmp_seq=2 ttl=64 time=0.0 ms (DUP!)
64 bytes from 172.16.1.2: icmp_seq=2 ttl=63 time=9.7 ms (DUP!)
--- drylab2.FastNet ping statistics ---
3 packets transmitted, 3 packets received, +9 duplicates, 0% packet loss
round-trip min/avg/max = 0.0/6.4/19.5 ms
Here is what 'traceroute' tells me:
traceroute drylab2
1 drylab3.FastNet (172.16.1.3) 0 ms (ttl=64!) 0 ms (ttl=64!) 10 ms (ttl=64!)
2 drylab2.FastNet (172.16.1.2) 10 ms (ttl=64!) 0 ms (ttl=64!) 0 ms (ttl=64!)
Any clues would be greatly appreciated!!!
Janice McCarthy
janice@acpub.duke.edu
