Switching a Network Interface on and off
Jonathan Hutchins
hutchins at opus1.com
Thu Apr 4 21:05:53 CST 2002
Is there a "best practice" way of switching a network interface on and off?
I'd like to be able to manually switch off, say, the interface to a given
subnet.
I have tried doing this using
# /sbin/ifconfig eth1 down
I can do that, and of course traffic from that card stops. When I do
# /sbin/ifconfig eth1 up
everything comes back just fine - UNLESS I wait too long.
I haven't defined "too long" yet, but it appears to be somewhere between a
few minutes and half an hour or so. If I wait too long, then while
# /sbin/ifconfig eth1 up
makes eth1 show up in both the output of # /sbin/ifconfig and of #
netstat -i, but the routing table entry shown by # netstat -r never recovers
the route to that network, and attempts to add it manually with the route
command yield "SIOCADDRT: No such device".
Basically, I have to restart the machine if I want the network back up. Oh,
and "/etc/rc.d/init.d/network restart doesn't seem to work, it hangs on pump
trying to get an address for the gateway interface.
This is a fairly stock RedHat 6.2 box with the 2.2.14-5.0 kernel.
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