On 9/15/2010 12:50 PM, Jeremy Charles wrote:
One of our server admins is telling me that his Solaris server's IP
multipathing software is checking connectivity to the default gateway
by sending ICMP echo requests addressed to the following:
MAC address ff:ff:ff:ff:ff:ff
IP address 0.0.0.0
He's telling me that the Solaris host is expecting to see the default
gateway respond to that.
Does anyone else view this as one or more of the following:
1) The actual expected behavior of Solaris IP multipathing
2) Something isn't completely configured
3) Non-intelligent design
My google-fu is coming up empty on trying to either substantiate this
as the expected behavior or provide troubleshooting help.
(The operational problem is that the Solaris host is in a subnet where
the default gateway is a Cisco Firewall Services Module, which doesn't
respond to the above. There are two Solaris hosts in that subnet and
they DO respond to those pings. Unfortunately, when one Solaris host
goes down, the other one stops seeing the ping responses, so it takes
down its services too.)
I haven't done anything with in.mpathd in a while, preferring to do
trunking almost exclusively anymore (LACP), but, there are 2 ways to do
mpathd that are documented.
1) using ICMP packets (though it leaves unspecified the precise details
of this. the one you mention above is plausible. I'd have to sniff an
in.mpathd before I answered this one, and I don't have one running)
2) using linkstate. You can set it to only watch the link state and then
do the failover.
Maybe you should configure mpathd to use method 2 in your circumstance,
though it is not without its own problems. It's perfectly plausible for
the link to be up and not passing any packets, especially when firewalls
are involved.
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