What's the purpose of dual LAN ports on a motherboard?

[Aztech]

How's dual LAN work on a motherboard? What's the 2nd one for?

Thanks, I'm shopping for motherboards and didn't know.

 

[alaricljs]

It's for having 2 network connections.

Depending on software and network switch support you can:
Bond the 2 channels (double the bandwidth)
Failover from 1 link to the other
Attach to 2 different networks, like if you have an isolated iSCSI or other IP storage network
attach to 2 different WAN connections and use your system as a router/load balancer