*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-P FORWARD ACCEPT
COMMIT
*nat
:PREROUTING ACCEPT [0:0]
:INPUT ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]
# Kreia is a client; Leibniz and Ferma are servers; port 1337 ; IP 5.7.1.42.
-A PREROUTING -i enp0s3 -p udp -d OLD_DST_IP -s SRC_IP -j DNAT --to-destination NEW_DST_IP
-A POSTROUTING -o enp0s3 -p udp -d SRC_IP -s NEW_DST_IP -j SNAT --to-source OLD_DST_IP
-A POSTROUTING -o enp0s3 -p udp -d SRC_IP -s ANOTHER_DST_IP -j SNAT --to-source OLD_DST_IP
COMMIT
*mangle
:PREROUTING ACCEPT [0:0]
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]
-A PREROUTING -i enp0s3 -p udp -s SRC_IP -d OLD_DST_IP -j TEE --gateway ANOTHER_DST_IP
COMMIT