root@xxx:~# cat /proc/sys/net/ipv4/ip_forward
1

root@xxx:~# netstat -tapln | grep :4545 | grep LISTEN
tcp        0      0 127.0.0.1:4545          0.0.0.0:*

root@xxx:~# curl -x socks5h://127.0.0.1:4545 ifconfig.co
1.2.3.4

iptables -P FORWARD ACCEPT
iptables -t nat -A POSTROUTING -j MASQUERADE
iptables -t nat -A PREROUTING -p tcp -j REDIRECT --to-ports 4545

root@xxx:~# curl ifconfig.co
9.8.7.6