| Custom Signature Pattern Requirements | All versions | You can enter hex-based patterns
by surrounding the bytes with ‘\x’. Most signature patterns can contain a maximum of 127 characters. If
you need to use a pattern longer than 127 characters, create two
separate conditions—one beginning where the other left off—and join
them with ‘AND’. You can still use Ordered Condition
Matchto require the firewall to consider one condition
before the other to ensure a closer match to the full string. - PA-220 and PA-800 appliances running PAN-OS 10.2 and
later support a maximum pattern length of 64 characters
for the following contexts: tcp-context-free and
udp-context-free.
Signature compilation processes can cause other
signatures to support a maximum pattern length of
64 characters, however, this is a rare
occurrence. As noted above, you can also create a pattern
that is longer that the maximum size of 64
characters by creating two separate
conditions.
Some application decoders may be case-sensitive for a given
field, depending on the decoder the firewall uses. For this reason,
you should define variations of the pattern. For example, \.CNN\.com
and \.cnn\.com will ensure your signature functions properly regardless
of case.
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