I have several servers that we have bonded some NICs for rundancy and they will of course switch from primary to secondary NIC if connection state is lost to the switches they are physically connected to, but is there any way to be able to sense upstream connectivity (off switch) for each NIC and failover even though the NIC itself has a connection state to the switch it is plugged into? We are using Dell managed switches on VLANs with trunking. Thanks for any input.

1. Keep failsafe disabled.
2. Have a script pull data from an upstream server periodically.
3. If data is unavailable then connection must be severed so switch on the failsafe nic and disable the downed nic.
4. Detect when new nic has an IP (with a timeout for obtaining an IP). When it gets an IP then attempt to pull the upstream data.
5. Repeat the process if failed to pull upstream data or if obtaining IP timeout is reached until one of the nics have connectivity.

I don't have time right now but I'll attempt to hack a script together in XYZ language which would be capable of doing that. You can use a number of any languages such as perl, python, or even shell to accomplish that process though.

Thanks sag47,

I have some folks that could script this, I just thought there may be something within the driver module or possibly another package/protocol that was created for this very thing.

It seems this would not be an unusual requirement for redundancy.

JTollack

Well you may be right but I am not very familiar with the network stacks of Linux. I just attempted to give you a pseudo solution. If I can come up with, or find something better then I'll certainly post it here.