iptables syntax

Applications IP Networking
1

Hi,
Can someone help to explain what is --to-source in
the iptables rule below:

iptables -t nat -A POSTROUTING -s 192.168.1.100 -o eth0 \
          -j SNAT --to-source 97.158.253.26

especially why the option has double dash (--)
is it a comment?

Thanks

2

The double dash means it's a long option (more than 1 character), and since it's a SNAT target I'd say it rewrites the source address on outgoing traffic.