IPv6 ALG support for FTP (NAT, NAT-PT support)

FTP represents the addresses and port numbers in ASCII. As a result, when addresses and ports are rewritten, the TCP sequence number might be changed, and thereafter the NAT service needs to maintain this delta in SEQ and ACK numbers by performing sequence NAT on all subsequent packets.

The FTP ALG supports rewriting the control packets with the appropriate NAT address and port information and Network Address Translation, Protocol Translation (NAT-PT).