Bug 10125 - ifup problem
Summary: ifup problem
Alias: None
Product: Red Hat Linux
Classification: Retired
Component: initscripts
Version: 6.2
Hardware: i386
OS: Linux
Target Milestone: ---
Assignee: Bill Nottingham
QA Contact:
Depends On:
TreeView+ depends on / blocked
Reported: 2000-03-11 18:42 UTC by Andreas J. Bathe
Modified: 2014-03-17 02:12 UTC (History)
2 users (show)

Clone Of:
Last Closed: 2000-08-17 11:50:38 UTC

Attachments (Terms of Use)

Description Andreas J. Bathe 2000-03-11 18:42:46 UTC
We have to do the following routing (done manually) which the ifup-
script can't handle:

Kernel IP routing table
Destination    Gateway         Genmask         Flags Metric Ref Use Iface
x.y.z.178 UH    0      0     0 eth0
x.y.z.177 UH    0      0     0 eth0
x.y.z.176 U     0      0     0 eth1   U     0      0     0 eth2        x.y.z.177         UG    0      0     0 eth0

x.y.z.178 is a firewall machine connected to a cicso router (x.y.z.177)
with a twisted pair crosslink cable (no hup will be used). x.y.z.176 is
a subnet from our provider used for a demilitarizied zone and are reach-
able via interface eth1 (with one exception: the cisco router). all local
machines are connected via the eth2 interface.

the ifup-script is not able to handle that specific situation where a
point-to-point connection is made across two interfaces, but within a

The other point is: the host-routes, are they really necessary? Or could
the part of the /sbin/ipup-script
--- cut ---
    # stupid hack, but it should work
    if [ "$ISALIAS" = no ] && [ -z "`route -n | sed "s/ .*//" | grep
${NETWORK}`" ]; then
        route add -net ${NETWORK} netmask ${NETMASK} dev ${DEVICE}
        route add -host ${IPADDR} ${DEVICE}
--- cut ---
replaced by this:
--- cut ---
    if [ "${NETMASK}" = "" ]; then
        route add -host ${IPADDR} ${DEVICE}
--- cut ---

Thanx for considering this point...
Andreas J. Bathe <ajb@allmaxx.de>

Comment 1 Andreas J. Bathe 2000-03-11 19:01:59 UTC
Forgot to tell you the ifcfg-files:

ifcfg-eth0:	DEVICE=eth0

ifcfg-eth1:	DEVICE=eth1

ifcfg-eth2:	DEVICE=eth2

in /etc/sysconfig/network:

Take care
Andreas J. Bathe <ajb@allmaxx.de>

Comment 2 Bill Nottingham 2000-03-20 17:24:59 UTC
Your ifcfg-eth0 looks wrong; it should have the
netmask, if I'm reading it correctly.

What it looks like you'd want is to put the eth0 and eth1
host routes in /etc/sysconfig/static-routes, something like

eth0 host x.y.z.178 eth0

Or am I misunderstanding what you're trying to do?

Comment 3 Bill Nottingham 2000-03-20 17:25:59 UTC
(make that just the eth0 routes, the eth1 config is fine.)

Comment 4 Andreas J. Bathe 2000-03-22 11:20:59 UTC
in /etc/sysconfig/static-routes there is the entry:
	eth0 host

at this point (till the rh-scripts will consider the described situation) the
gateway will be set via the /etc/rc.d/rc.local-script with:
	route add default gw

At boottime we get the message:
Mar 16 06:38:53 gateway kernel: eth1: media is 100Mb/s.
Mar 16 06:38:50 gateway network: Bringing up interface lo succeeded
Mar 16 06:38:50 gateway ifup: SIOCADDRT: Network is unreachable
Mar 16 06:38:50 gateway network: Bringing up interface eth0 succeeded
Mar 16 06:38:51 gateway network: Bringing up interface eth1 succeeded
Mar 16 06:38:51 gateway network: Bringing up interface eth2 succeeded
Mar 16 06:38:53 gateway kernel: eth2: media is 100Mb/s.

The net x.y.z.176 net is on eth1 (all machines with the exception of the
cisco x.y.z.177). If eth0 would have the netmask all traffic
would go to eth0 which would be wrong. on eth0 there are only the gateway
x.y.z.178 (our firewall) connected to the cisco-router (x.y.z.177).

Comment 5 keith.moore 2000-08-17 11:48:44 UTC
Well, this is definitely and odd setup, since you want two Network cards with
the same IP, but different subnet masks.   It sounds like you are trying to
emulate a bridging firewall.

If this is the case, the subnetmask is not really it's for that card, but that would give you a network number and
broadcast number also (Which is not really what you want).  You are technically
creating an invalid network (No network/broadcast), but if you configure it with in the ifcfg-eth0, and add the static host route, it should work
for you.

The suggested fix will work, but as stated does not really create a valid
network.  You would have to make other changes also (Point-To-Point on the

-- Keith Moore

Comment 6 keith.moore 2000-08-17 11:50:35 UTC
A clarification to my last paragraph, I was refering to the ifup patch would not
be a valid fix, since it doesn't configure the card properly.

Comment 7 Bill Nottingham 2001-01-30 00:56:19 UTC
In general, we aren't going to support such esoteric network
configs out-of-the-box.

Note You need to log in before you can comment on or make changes to this bug.