/usr/share/doc/nftables/examples/nat.nft

#!/usr/sbin/nft -f

table ip nat {
        chain prerouting {
                type nat hook prerouting priority 0;

                #Thanks to nftables maps, if you have a previous iptables NAT (destination NAT) ruleset like this:
                # % iptables -t nat -A PREROUTING -p tcp --dport 1000 -j DNAT --to-destination 1.1.1.1:1234
                # % iptables -t nat -A PREROUTING -p udp --dport 2000 -j DNAT --to-destination 2.2.2.2:2345
                # % iptables -t nat -A PREROUTING -p tcp --dport 3000 -j DNAT --to-destination 3.3.3.3:3456

                # It can be easily translated to nftables in a single line:

                dnat tcp dport map { 1000 : 1.1.1.1, 2000 : 2.2.2.2, 3000 : 3.3.3.3} \
                                : tcp dport map { 1000 : 1234, 2000 : 2345, 3000 : 3456 }
        }

        chain postrouting {
                type nat hook postrouting priority 0;

                #Likewise, in iptables NAT (source NAT):
                # % iptables -t nat -A POSTROUTING -s 192.168.1.1 -j SNAT --to-source 1.1.1.1
                # % iptables -t nat -A POSTROUTING -s 192.168.2.2 -j SNAT --to-source 2.2.2.2
                # % iptables -t nat -A POSTROUTING -s 192.168.3.3 -j SNAT --to-source 3.3.3.3

                # Translated to a nftables one-liner:

                snat ip saddr map { 192.168.1.1 : 1.1.1.1, 192.168.2.2 : 2.2.2.2, 192.168.3.3 : 3.3.3.3 }
        }
}

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