Iptables

To forward packets sent to one IP over to a different IP on a different server, you can use iptables.

OLD_IP=92.48.119.131
NEW_IP=213.229.103.79

OLD_PORT=80
NEW_PORT=80

iptables -t nat -A PREROUTING -d $OLD_IP -p tcp -m tcp --dport $OLD_PORT -j DNAT --to-destination $NEW_IP:$NEW_PORT
iptables -t nat -A POSTROUTING ! -s $OLD_IP -d $NEW_IP -p tcp -m tcp --dport $NEW_PORT -j SNAT --to-source $OLD_IP

Blanket allow all packets being forwarded to the new IP.

iptables -I FORWARD -d $NEW_IP -j ACCEPT
iptables -I FORWARD -s $NEW_IP -j ACCEPT

Things to watch for if it doesn't work - IP forwarding needs to be enabled (sysctl -w net.ipv4.ip_forward=1) and you may need to allow the specific port in the INPUT chain. Not sure about this as I had already allowed port 80 prior to setting up the forwarding.