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# Redirect TCP/IP traffic to a particular IP address from one port to another
# port. This is useful to handle incoming traffic on a standard reserved port
# like 80 or 443 for example in an unprivileged user process bound to a non
# reserved port.
# Example: ip-redirect 80 8090 10.1.1.1

sport=$1
tport=$2
dest=$3

# Redirect external incoming traffic
sudo /sbin/iptables -t nat -A PREROUTING --destination $dest -p tcp --dport $sport -j REDIRECT --to-port $tport

# Redirect local traffic as well
sudo /sbin/iptables -t nat -A OUTPUT --destination $dest -p tcp --dport $sport -j REDIRECT --to-port $tport