Proxy support in miniupnpd
Created by: pali
Now some ISPs which put end IPv4 users behind Carrier-Grade NATs started supporting PCP.
So if end user with his own IPv4 router (which does NAT for his own local network) wants to use PCP support from ISP, then he needs to run something like PCP proxy on his router.
I would suggest to implement PCP proxy in miniupnpd. When client from internal network ask for port forwarding then miniupnpd would try to request for port forwarding via external interface to upstream ISP network.
This would also allow to connect one miniupnpd router behind another miniupnpd router with working IPv4 address forwarding.