Redundant NICs on Solaris
By Tom Kranz, May 13, 2004
You have your resilient network in place. Dual switches, dual routers, HSRP, failover, redundant firewalls -- they're all there. Now, what about your Sun boxes? Having two network interface cards (NICs) on your Solaris server, with the primary NIC failing over to the secondary, seems like an obvious and easy task, yet there are many pitfalls that make it unnecessarily complicated. In this article, I'm going to explore how to provide redundant NICs simply and cheaply.
Listing 1 if_check.sh
#!/bin/sh
#
# 2001-01-30 Tom Kranz ([email protected])
#
# We return the following error codes:
# 0 - network connectivity is OK as it as - apart from annoyingly printing
# 'Woohoo' nothing has happened
# 1 - something's fubar on the network, and we've had to swap interfaces
# 2 - you didn't enter a IP address to ping to test connectivity - we'll
# print a nice error message and then leave
if [ $# -ne 1 ]
then
echo
echo "Usage: if_checker.sh <IP_address_to_ping>"
echo
echo "Where <IP_address_to_ping> is an always-reachable address you can"
echo "use to verify connectivity"
echo
exit 2
fi
if /usr/sbin/ping $1
then
echo "Woohoo!"
exit 0
else
upif="`/usr/sbin/ifconfig -a | grep -v LOOPBACK | grep UP | cut -b 1-4`"
downif="`/usr/sbin/ifconfig -a | grep -v LOOPBACK | grep -v UP | grep RU \
NNING | cut -b 1-4`"
/usr/sbin/ifconfig $upif down
/usr/sbin/ifconfig $downif up
fi
/usr/sbin/ping $1
exit 1
