I add multiple addresses per interface (WAN) on the same subnet.
Only one IP (first) available from global network (ping, traceroute etc).
I desable all IP addresses on nic and enable only one. This IP becomes available from global network.
So do all in turn
Then turn on all.
All IP becomes available from global network.

Problems with me? Do provider?
Do provider Cisco 2960.
Help me please.

I used IPv4