Table 35 Relational operators for capture filters
Nonalphanumeric
symbol
=
!=
>
<
>=
<=
Display filter keywords
Table 36
and
Table 36 Qualifiers for display filters
Category
Protocol
Packet field
NOTE:
The protocol qualifiers cannot modify variables.
Table 37 Variable types for display filters
Variable
type
Integer
Description
Equal to.
For example, ip[6]=0x1c matches an IPv4 packet if its seventh byte of payload is
equal to 0x1c.
Not equal to.
For example, len!=60 matches a packet if its length is not equal to 60 bytes.
Greater than.
For example, len>100 matches a packet if its length is greater than 100 bytes.
Less than.
For example, len<100 matches a packet if its length is less than 100 bytes.
Greater than or equal to.
For example, len>=100 matches a packet if its length is greater than or equal to
100 bytes.
Less than or equal to.
For example, len<=100 matches a packet if its length is less than or equal to 100
bytes.
Table 37
describe the qualifiers and variables for display filters, respectively.
Description
Matches a protocol.
Matches a field in packets by using a
dotted string in the
protocol.field[.level1-subfield]...[.leveln-
subfield] format.
Description
Represented in binary, octal, decimal, or hexadecimal notation.
For example, to display IP packets that are less than or equal to 1500 bytes, use one of the
following expressions:
Examples
•
eth—Matches Ethernet.
•
ftp—Matches FTP.
•
http—Matches HTTP.
•
icmp—Matches ICMP.
•
ip—Matches IPv4.
•
ipv6—Matches IPv6.
•
tcp—Matches TCP.
•
telnet—Matches Telnet.
•
udp—Matches UDP.
•
tcp.flags.syn—Matches the SYN bit in the
flags field of TCP.
•
tcp.port—Matches the source or
destination port field.
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