specify a range of IP addresses or ports using iptables

To specify a range of IP addresses or ports, use a dash. When using IP addresses and ports in conjunction, use a colon to separate. For example:

IP-IP:Port-Port

IP address ranges are only valid in the nat table, using the options --to-source and --to-destination. When a range is given, a simple round-robin (one after another in cycle) takes place between these adresses.

For example, when using NAT you can map to a range of possible IP addresses with:

# iptables -t nat -A POSTROUTING -j SNAT --to-source 1.2.3.45-1.2.3.55

and you can map to a range of possible ports with:

# iptables -t nat -A POSTROUTING -j SNAT --to-source 1.2.3.45:1234-1334