Installing and Administering PPP

Chapter 5 97

Security Techniques

Building a Stanza - General

Some general concepts to remember when writing a stanza are listed

here:

• Each stanza includes one or more numbers, addresses, or keywords,

separated by slashes (/).

• Each number, address, or keyword adds an additional qualiﬁer to the

stanza.

• Each qualiﬁer or pattern must match for the rule to be applied to the

packet.

• A stanza can be used to either permit or deny a matching packet.

• Begin with the negation operator (!) to block or deny a packet.

• Any stanza that is not negated permits matching packets.

• Comments begin with a ‘#' character and extend through the end of

the line.