1PCAP-FILTER(7) Miscellaneous Information Manual PCAP-FILTER(7)
2
6 pcap-filter - packet filter syntax
7
9 pcap_compile() is used to compile a string into a filter program. The
10 resulting filter program can then be applied to some stream of packets
11 to determine which packets will be supplied to pcap_loop(), pcap_dis‐
12 patch(), pcap_next(), or pcap_next_ex().
13 The filter expression consists of one or more primitives. Primitives
15 usually consist of an id (name or number) preceded by one or more qual‐
16 ifiers. There are three different kinds of qualifier:
17 type type qualifiers say what kind of thing the id name or number
19 refers to. Possible types are host, net , port and portrange.
20 E.g., `host foo', `net 128.3', `port 20', `portrange 6000-6008'.
21 If there is no type qualifier, host is assumed.
22 dir dir qualifiers specify a particular transfer direction to and/or
24 from id. Possible directions are src, dst, src or dst, src and
25 dst, ra, ta, addr1, addr2, addr3, and addr4. E.g., `src foo',
26 `dst net 128.3', `src or dst port ftp-data'. If there is no dir
27 qualifier, src or dst is assumed. The ra, ta, addr1, addr2,
28 addr3, and addr4 qualifiers are only valid for IEEE 802.11 Wire‐
29 less LAN link layers. For some link layers, such as SLIP and
30 the ``cooked'' Linux capture mode used for the ``any'' device
31 and for some other device types, the inbound and outbound quali‐
32 fiers can be used to specify a desired direction.
33 proto proto qualifiers restrict the match to a particular protocol.
35 Possible protos are: ether, fddi, tr, wlan, ip, ip6, arp, rarp,
36 decnet, tcp and udp. E.g., `ether src foo', `arp net 128.3',
37 `tcp port 21', `udp portrange 7000-7009', `wlan addr2
38 0:2:3:4:5:6'. If there is no proto qualifier, all protocols
39 consistent with the type are assumed. E.g., `src foo' means
40 `(ip or arp or rarp) src foo' (except the latter is not legal
41 syntax), `net bar' means `(ip or arp or rarp) net bar' and `port
42 53' means `(tcp or udp) port 53'.
43 [`fddi' is actually an alias for `ether'; the parser treats them iden‐
45 tically as meaning ``the data link level used on the specified network
46 interface.'' FDDI headers contain Ethernet-like source and destination
47 addresses, and often contain Ethernet-like packet types, so you can
48 filter on these FDDI fields just as with the analogous Ethernet fields.
49 FDDI headers also contain other fields, but you cannot name them
50 explicitly in a filter expression.
51 Similarly, `tr' and `wlan' are aliases for `ether'; the previous para‐
53 graph's statements about FDDI headers also apply to Token Ring and
54 802.11 wireless LAN headers. For 802.11 headers, the destination
55 address is the DA field and the source address is the SA field; the
56 BSSID, RA, and TA fields aren't tested.]
57 In addition to the above, there are some special `primitive' keywords
59 that don't follow the pattern: gateway, broadcast, less, greater and
60 arithmetic expressions. All of these are described below.
61 More complex filter expressions are built up by using the words and, or
63 and not to combine primitives. E.g., `host foo and not port ftp and
64 not port ftp-data'. To save typing, identical qualifier lists can be
65 omitted. E.g., `tcp dst port ftp or ftp-data or domain' is exactly the
66 same as `tcp dst port ftp or tcp dst port ftp-data or tcp dst port
67 domain'.
68 Allowable primitives are:
70 dst host host
72 True if the IPv4/v6 destination field of the packet is host,
73 which may be either an address or a name.
74 src host host
76 True if the IPv4/v6 source field of the packet is host.
77 host host
79 True if either the IPv4/v6 source or destination of the packet
80 is host.
81 Any of the above host expressions can be prepended with the key‐
83 words, ip, arp, rarp, or ip6 as in:
84 ip host host
85 which is equivalent to:
86 ether proto \ip and host host
87 If host is a name with multiple IP addresses, each address will
88 be checked for a match.
89 ether dst ehost
91 True if the Ethernet destination address is ehost. Ehost may be
92 either a name from /etc/ethers or a number (see ethers(3N) for
93 numeric format).
94 ether src ehost
96 True if the Ethernet source address is ehost.
97 ether host ehost
99 True if either the Ethernet source or destination address is
100 ehost.
101 gateway host
103 True if the packet used host as a gateway. I.e., the Ethernet
104 source or destination address was host but neither the IP source
105 nor the IP destination was host. Host must be a name and must
106 be found both by the machine's host-name-to-IP-address resolu‐
107 tion mechanisms (host name file, DNS, NIS, etc.) and by the
108 machine's host-name-to-Ethernet-address resolution mechanism
109 (/etc/ethers, etc.). (An equivalent expression is
110 ether host ehost and not host host
111 which can be used with either names or numbers for host /
112 ehost.) This syntax does not work in IPv6-enabled configuration
113 at this moment.
114 dst net net
116 True if the IPv4/v6 destination address of the packet has a net‐
117 work number of net. Net may be either a name from the networks
118 database (/etc/networks, etc.) or a network number. An IPv4
119 network number can be written as a dotted quad (e.g.,
120 192.168.1.0), dotted triple (e.g., 192.168.1), dotted pair (e.g,
121 172.16), or single number (e.g., 10); the netmask is
122 255.255.255.255 for a dotted quad (which means that it's really
123 a host match), 255.255.255.0 for a dotted triple, 255.255.0.0
124 for a dotted pair, or 255.0.0.0 for a single number. An IPv6
125 network number must be written out fully; the netmask is
126 ff:ff:ff:ff:ff:ff:ff:ff, so IPv6 "network" matches are really
127 always host matches, and a network match requires a netmask
128 length.
129 src net net
131 True if the IPv4/v6 source address of the packet has a network
132 number of net.
133 net net
135 True if either the IPv4/v6 source or destination address of the
136 packet has a network number of net.
137 net net mask netmask
139 True if the IPv4 address matches net with the specific netmask.
140 May be qualified with src or dst. Note that this syntax is not
141 valid for IPv6 net.
142 net net/len
144 True if the IPv4/v6 address matches net with a netmask len bits
145 wide. May be qualified with src or dst.
146 dst port port
148 True if the packet is ip/tcp, ip/udp, ip6/tcp or ip6/udp and has
149 a destination port value of port. The port can be a number or a
150 name used in /etc/services (see tcp(4P) and udp(4P)). If a name
151 is used, both the port number and protocol are checked. If a
152 number or ambiguous name is used, only the port number is
153 checked (e.g., dst port 513 will print both tcp/login traffic
154 and udp/who traffic, and port domain will print both tcp/domain
155 and udp/domain traffic).
156 src port port
158 True if the packet has a source port value of port.
159 port port
161 True if either the source or destination port of the packet is
162 port.
163 dst portrange port1-port2
165 True if the packet is ip/tcp, ip/udp, ip6/tcp or ip6/udp and has
166 a destination port value between port1 and port2. port1 and
167 port2 are interpreted in the same fashion as the port parameter
168 for port.
169 src portrange port1-port2
171 True if the packet has a source port value between port1 and
172 port2.
173 portrange port1-port2
175 True if either the source or destination port of the packet is
176 between port1 and port2.
177 Any of the above port or port range expressions can be prepended
179 with the keywords, tcp or udp, as in:
180 tcp src port port
181 which matches only tcp packets whose source port is port.
182 less length
184 True if the packet has a length less than or equal to length.
185 This is equivalent to:
186 len <= length.
187 greater length
189 True if the packet has a length greater than or equal to length.
190 This is equivalent to:
191 len >= length.
192 ip proto protocol
194 True if the packet is an IPv4 packet (see ip(4P)) of protocol
195 type protocol. Protocol can be a number or one of the names
196 icmp, icmp6, igmp, igrp, pim, ah, esp, vrrp, udp, or tcp. Note
197 that the identifiers tcp, udp, and icmp are also keywords and
198 must be escaped via backslash (\), which is \\ in the C-shell.
199 Note that this primitive does not chase the protocol header
200 chain.
201 ip6 proto protocol
203 True if the packet is an IPv6 packet of protocol type protocol.
204 Note that this primitive does not chase the protocol header
205 chain.
206 proto protocol
208 True if the packet is an IPv4 or IPv6 packet of protocol type
209 protocol. Note that this primitive does not chase the protocol
210 header chain.
211 tcp, udp, icmp
213 Abbreviations for:
214 proto p
215 where p is one of the above protocols.
216 ip6 protochain protocol
218 True if the packet is IPv6 packet, and contains protocol header
219 with type protocol in its protocol header chain. For example,
220 ip6 protochain 6
221 matches any IPv6 packet with TCP protocol header in the protocol
222 header chain. The packet may contain, for example, authentica‐
223 tion header, routing header, or hop-by-hop option header,
224 between IPv6 header and TCP header. The BPF code emitted by
225 this primitive is complex and cannot be optimized by the BPF
226 optimizer code, so this can be somewhat slow.
227 ip protochain protocol
229 Equivalent to ip6 protochain protocol, but this is for IPv4.
230 protochain protocol
232 True if the packet is an IPv4 or IPv6 packet of protocol type
233 protocol. Note that this primitive chases the protocol header
234 chain.
235 ether broadcast
237 True if the packet is an Ethernet broadcast packet. The ether
238 keyword is optional.
239 ip broadcast
241 True if the packet is an IPv4 broadcast packet. It checks for
242 both the all-zeroes and all-ones broadcast conventions, and
243 looks up the subnet mask on the interface on which the capture
244 is being done.
245 If the subnet mask of the interface on which the capture is
247 being done is not available, either because the interface on
248 which capture is being done has no netmask or because the cap‐
249 ture is being done on the Linux "any" interface, which can cap‐
250 ture on more than one interface, this check will not work cor‐
251 rectly.
252 ether multicast
254 True if the packet is an Ethernet multicast packet. The ether
255 keyword is optional. This is shorthand for `ether[0] & 1 != 0'.
256 ip multicast
258 True if the packet is an IPv4 multicast packet.
259 ip6 multicast
261 True if the packet is an IPv6 multicast packet.
262 ether proto protocol
264 True if the packet is of ether type protocol. Protocol can be a
265 number or one of the names ip, ip6, arp, rarp, atalk, aarp, dec‐
266 net, sca, lat, mopdl, moprc, iso, stp, ipx, or netbeui. Note
267 these identifiers are also keywords and must be escaped via
268 backslash (\).
269 [In the case of FDDI (e.g., `fddi protocol arp'), Token Ring
271 (e.g., `tr protocol arp'), and IEEE 802.11 wireless LANS (e.g.,
272 `wlan protocol arp'), for most of those protocols, the protocol
273 identification comes from the 802.2 Logical Link Control (LLC)
274 header, which is usually layered on top of the FDDI, Token Ring,
275 or 802.11 header.
276 When filtering for most protocol identifiers on FDDI, Token
278 Ring, or 802.11, the filter checks only the protocol ID field of
279 an LLC header in so-called SNAP format with an Organizational
280 Unit Identifier (OUI) of 0x000000, for encapsulated Ethernet; it
281 doesn't check whether the packet is in SNAP format with an OUI
282 of 0x000000. The exceptions are:
283 iso the filter checks the DSAP (Destination Service Access
285 Point) and SSAP (Source Service Access Point) fields of
286 the LLC header;
287 stp and netbeui
289 the filter checks the DSAP of the LLC header;
290 atalk the filter checks for a SNAP-format packet with an OUI of
292 0x080007 and the AppleTalk etype.
293 In the case of Ethernet, the filter checks the Ethernet type
295 field for most of those protocols. The exceptions are:
296 iso, stp, and netbeui
298 the filter checks for an 802.3 frame and then checks the
299 LLC header as it does for FDDI, Token Ring, and 802.11;
300 atalk the filter checks both for the AppleTalk etype in an Eth‐
302 ernet frame and for a SNAP-format packet as it does for
303 FDDI, Token Ring, and 802.11;
304 aarp the filter checks for the AppleTalk ARP etype in either
306 an Ethernet frame or an 802.2 SNAP frame with an OUI of
307 0x000000;
308 ipx the filter checks for the IPX etype in an Ethernet frame,
310 the IPX DSAP in the LLC header, the 802.3-with-no-LLC-
311 header encapsulation of IPX, and the IPX etype in a SNAP
312 frame.
313 ip, ip6, arp, rarp, atalk, aarp, decnet, iso, stp, ipx, netbeui
315 Abbreviations for:
316 ether proto p
317 where p is one of the above protocols.
318 lat, moprc, mopdl
320 Abbreviations for:
321 ether proto p
322 where p is one of the above protocols. Note that not all appli‐
323 cations using pcap(3PCAP) currently know how to parse these pro‐
324 tocols.
325 decnet src host
327 True if the DECNET source address is host, which may be an
328 address of the form ``10.123'', or a DECNET host name. [DECNET
329 host name support is only available on ULTRIX systems that are
330 configured to run DECNET.]
331 decnet dst host
333 True if the DECNET destination address is host.
334 decnet host host
336 True if either the DECNET source or destination address is host.
337 ifname interface
339 True if the packet was logged as coming from the specified
340 interface (applies only to packets logged by OpenBSD's or Free‐
341 BSD's pf(4)).
342 on interface
344 Synonymous with the ifname modifier.
345 rnr num
347 True if the packet was logged as matching the specified PF rule
348 number (applies only to packets logged by OpenBSD's or FreeBSD's
349 pf(4)).
350 rulenum num
352 Synonymous with the rnr modifier.
353 reason code
355 True if the packet was logged with the specified PF reason code.
356 The known codes are: match, bad-offset, fragment, short, normal‐
357 ize, and memory (applies only to packets logged by OpenBSD's or
358 FreeBSD's pf(4)).
359 rset name
361 True if the packet was logged as matching the specified PF rule‐
362 set name of an anchored ruleset (applies only to packets logged
363 by OpenBSD's or FreeBSD's pf(4)).
364 ruleset name
366 Synonomous with the rset modifier.
367 srnr num
369 True if the packet was logged as matching the specified PF rule
370 number of an anchored ruleset (applies only to packets logged by
371 OpenBSD's or FreeBSD's pf(4)).
372 subrulenum num
374 Synonomous with the srnr modifier.
375 action act
377 True if PF took the specified action when the packet was logged.
378 Known actions are: pass and block and, with later versions of
379 pf(4)), nat, rdr, binat and scrub (applies only to packets
380 logged by OpenBSD's or FreeBSD's pf(4)).
381 wlan ra ehost
383 True if the IEEE 802.11 RA is ehost. The RA field is used in
384 all frames except for management frames.
385 wlan ta ehost
387 True if the IEEE 802.11 TA is ehost. The TA field is used in
388 all frames except for management frames and CTS (Clear To Send)
389 and ACK (Acknowledgment) control frames.
390 wlan addr1 ehost
392 True if the first IEEE 802.11 address is ehost.
393 wlan addr2 ehost
395 True if the second IEEE 802.11 address, if present, is ehost.
396 The second address field is used in all frames except for CTS
397 (Clear To Send) and ACK (Acknowledgment) control frames.
398 wlan addr3 ehost
400 True if the third IEEE 802.11 address, if present, is ehost.
401 The third address field is used in management and data frames,
402 but not in control frames.
403 wlan addr4 ehost
405 True if the fourth IEEE 802.11 address, if present, is ehost.
406 The fourth address field is only used for WDS (Wireless Distri‐
407 bution System) frames.
408 type wlan_type
410 True if the IEEE 802.11 frame type matches the specified
411 wlan_type. Valid wlan_types are: mgt, ctl and data.
412 type wlan_type subtype wlan_subtype
414 True if the IEEE 802.11 frame type matches the specified
415 wlan_type and frame subtype matches the specified wlan_subtype.
416 If the specified wlan_type is mgt, then valid wlan_subtypes are:
418 assoc-req, assoc-resp, reassoc-req, reassoc-resp, probe-req,
419 probe-resp, beacon, atim, disassoc, auth and deauth.
420 If the specified wlan_type is ctl, then valid wlan_subtypes are:
422 ps-poll, rts, cts, ack, cf-end and cf-end-ack.
423 If the specified wlan_type is data, then valid wlan_subtypes
425 are: data, data-cf-ack, data-cf-poll, data-cf-ack-poll, null,
426 cf-ack, cf-poll, cf-ack-poll, qos-data, qos-data-cf-ack, qos-
427 data-cf-poll, qos-data-cf-ack-poll, qos, qos-cf-poll and qos-cf-
428 ack-poll.
429 subtype wlan_subtype
431 True if the IEEE 802.11 frame subtype matches the specified
432 wlan_subtype and frame has the type to which the specified
433 wlan_subtype belongs.
434 dir dir
436 True if the IEEE 802.11 frame direction matches the specified
437 dir. Valid directions are: nods, tods, fromds, dstods, or a
438 numeric value.
439 vlan [vlan_id]
441 True if the packet is an IEEE 802.1Q VLAN packet. If [vlan_id]
442 is specified, only true if the packet has the specified vlan_id.
443 Note that the first vlan keyword encountered in expression
444 changes the decoding offsets for the remainder of expression on
445 the assumption that the packet is a VLAN packet. The vlan
446 [vlan_id] expression may be used more than once, to filter on
447 VLAN hierarchies. Each use of that expression increments the
448 filter offsets by 4.
449 For example:
451 vlan 100 && vlan 200
452 filters on VLAN 200 encapsulated within VLAN 100, and
453 vlan && vlan 300 && ip
454 filters IPv4 protocols encapsulated in VLAN 300 encapsulated
455 within any higher order VLAN.
456 mpls [label_num]
458 True if the packet is an MPLS packet. If [label_num] is speci‐
459 fied, only true is the packet has the specified label_num. Note
460 that the first mpls keyword encountered in expression changes
461 the decoding offsets for the remainder of expression on the
462 assumption that the packet is a MPLS-encapsulated IP packet.
463 The mpls [label_num] expression may be used more than once, to
464 filter on MPLS hierarchies. Each use of that expression incre‐
465 ments the filter offsets by 4.
466 For example:
468 mpls 100000 && mpls 1024
469 filters packets with an outer label of 100000 and an inner label
470 of 1024, and
471 mpls && mpls 1024 && host 192.9.200.1
472 filters packets to or from 192.9.200.1 with an inner label of
473 1024 and any outer label.
474 pppoed True if the packet is a PPP-over-Ethernet Discovery packet (Eth‐
476 ernet type 0x8863).
477 pppoes [session_id]
479 True if the packet is a PPP-over-Ethernet Session packet (Ether‐
480 net type 0x8864). If [session_id] is specified, only true if
481 the packet has the specified session_id. Note that the first
482 pppoes keyword encountered in expression changes the decoding
483 offsets for the remainder of expression on the assumption that
484 the packet is a PPPoE session packet.
485 For example:
487 pppoes 0x27 && ip
488 filters IPv4 protocols encapsulated in PPPoE session id 0x27.
489 iso proto protocol
491 True if the packet is an OSI packet of protocol type protocol.
492 Protocol can be a number or one of the names clnp, esis, or
493 isis.
494 clnp, esis, isis
496 Abbreviations for:
497 iso proto p
498 where p is one of the above protocols.
499 l1, l2, iih, lsp, snp, csnp, psnp
501 Abbreviations for IS-IS PDU types.
502 vpi n True if the packet is an ATM packet, for SunATM on Solaris, with
504 a virtual path identifier of n.
505 vci n True if the packet is an ATM packet, for SunATM on Solaris, with
507 a virtual channel identifier of n.
508 lane True if the packet is an ATM packet, for SunATM on Solaris, and
510 is an ATM LANE packet. Note that the first lane keyword encoun‐
511 tered in expression changes the tests done in the remainder of
512 expression on the assumption that the packet is either a LANE
513 emulated Ethernet packet or a LANE LE Control packet. If lane
514 isn't specified, the tests are done under the assumption that
515 the packet is an LLC-encapsulated packet.
516 llc True if the packet is an ATM packet, for SunATM on Solaris, and
518 is an LLC-encapsulated packet.
519 oamf4s True if the packet is an ATM packet, for SunATM on Solaris, and
521 is a segment OAM F4 flow cell (VPI=0 & VCI=3).
522 oamf4e True if the packet is an ATM packet, for SunATM on Solaris, and
524 is an end-to-end OAM F4 flow cell (VPI=0 & VCI=4).
525 oamf4 True if the packet is an ATM packet, for SunATM on Solaris, and
527 is a segment or end-to-end OAM F4 flow cell (VPI=0 & (VCI=3 |
528 VCI=4)).
529 oam True if the packet is an ATM packet, for SunATM on Solaris, and
531 is a segment or end-to-end OAM F4 flow cell (VPI=0 & (VCI=3 |
532 VCI=4)).
533 metac True if the packet is an ATM packet, for SunATM on Solaris, and
535 is on a meta signaling circuit (VPI=0 & VCI=1).
536 bcc True if the packet is an ATM packet, for SunATM on Solaris, and
538 is on a broadcast signaling circuit (VPI=0 & VCI=2).
539 sc True if the packet is an ATM packet, for SunATM on Solaris, and
541 is on a signaling circuit (VPI=0 & VCI=5).
542 ilmic True if the packet is an ATM packet, for SunATM on Solaris, and
544 is on an ILMI circuit (VPI=0 & VCI=16).
545 connectmsg
547 True if the packet is an ATM packet, for SunATM on Solaris, and
548 is on a signaling circuit and is a Q.2931 Setup, Call Proceed‐
549 ing, Connect, Connect Ack, Release, or Release Done message.
550 metaconnect
552 True if the packet is an ATM packet, for SunATM on Solaris, and
553 is on a meta signaling circuit and is a Q.2931 Setup, Call Pro‐
554 ceeding, Connect, Release, or Release Done message.
555 expr relop expr
557 True if the relation holds, where relop is one of >, <, >=, <=,
558 =, !=, and expr is an arithmetic expression composed of integer
559 constants (expressed in standard C syntax), the normal binary
560 operators [+, -, *, /, &, |, <<, >>], a length operator, and
561 special packet data accessors. Note that all comparisons are
562 unsigned, so that, for example, 0x80000000 and 0xffffffff are >
563 0. To access data inside the packet, use the following syntax:
564 proto [ expr : size ]
565 Proto is one of ether, fddi, tr, wlan, ppp, slip, link, ip, arp,
566 rarp, tcp, udp, icmp, ip6 or radio, and indicates the protocol
567 layer for the index operation. (ether, fddi, wlan, tr, ppp,
568 slip and link all refer to the link layer. radio refers to the
569 "radio header" added to some 802.11 captures.) Note that tcp,
570 udp and other upper-layer protocol types only apply to IPv4, not
571 IPv6 (this will be fixed in the future). The byte offset, rela‐
572 tive to the indicated protocol layer, is given by expr. Size is
573 optional and indicates the number of bytes in the field of
574 interest; it can be either one, two, or four, and defaults to
575 one. The length operator, indicated by the keyword len, gives
576 the length of the packet.
577 For example, `ether[0] & 1 != 0' catches all multicast traffic.
579 The expression `ip[0] & 0xf != 5' catches all IPv4 packets with
580 options. The expression `ip[6:2] & 0x1fff = 0' catches only
581 unfragmented IPv4 datagrams and frag zero of fragmented IPv4
582 datagrams. This check is implicitly applied to the tcp and udp
583 index operations. For instance, tcp[0] always means the first
584 byte of the TCP header, and never means the first byte of an
585 intervening fragment.
586 Some offsets and field values may be expressed as names rather
588 than as numeric values. The following protocol header field
589 offsets are available: icmptype (ICMP type field), icmpcode
590 (ICMP code field), and tcpflags (TCP flags field).
591 The following ICMP type field values are available: icmp-echore‐
593 ply, icmp-unreach, icmp-sourcequench, icmp-redirect, icmp-echo,
594 icmp-routeradvert, icmp-routersolicit, icmp-timxceed, icmp-
595 paramprob, icmp-tstamp, icmp-tstampreply, icmp-ireq, icmp-ire‐
596 qreply, icmp-maskreq, icmp-maskreply.
597 The following TCP flags field values are available: tcp-fin,
599 tcp-syn, tcp-rst, tcp-push, tcp-ack, tcp-urg.
600 Primitives may be combined using:
602 A parenthesized group of primitives and operators (parentheses
604 are special to the Shell and must be escaped).
605 Negation (`!' or `not').
607 Concatenation (`&&' or `and').
609 Alternation (`||' or `or').
611 Negation has highest precedence. Alternation and concatenation have
613 equal precedence and associate left to right. Note that explicit and
614 tokens, not juxtaposition, are now required for concatenation.
615 If an identifier is given without a keyword, the most recent keyword is
617 assumed. For example,
618 not host vs and ace
619 is short for
620 not host vs and host ace
621 which should not be confused with
622 not ( host vs or ace )
623
625 To select all packets arriving at or departing from sundown:
626 host sundown
627 To select traffic between helios and either hot or ace:
629 host helios and \( hot or ace \)
630 To select all IP packets between ace and any host except helios:
632 ip host ace and not helios
633 To select all traffic between local hosts and hosts at Berkeley:
635 net ucb-ether
636 To select all ftp traffic through internet gateway snup:
638 gateway snup and (port ftp or ftp-data)
639 To select traffic neither sourced from nor destined for local hosts (if
641 you gateway to one other net, this stuff should never make it onto your
642 local net).
643 ip and not net localnet
644 To select the start and end packets (the SYN and FIN packets) of each
646 TCP conversation that involves a non-local host.
647 tcp[tcpflags] & (tcp-syn|tcp-fin) != 0 and not src and dst net localnet
648 To select all IPv4 HTTP packets to and from port 80, i.e. print only
650 packets that contain data, not, for example, SYN and FIN packets and
651 ACK-only packets. (IPv6 is left as an exercise for the reader.)
652 tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)
653 To select IP packets longer than 576 bytes sent through gateway snup:
655 gateway snup and ip[2:2] > 576
656 To select IP broadcast or multicast packets that were not sent via Eth‐
658 ernet broadcast or multicast:
659 ether[0] & 1 = 0 and ip[16] >= 224
660 To select all ICMP packets that are not echo requests/replies (i.e.,
662 not ping packets):
663 icmp[icmptype] != icmp-echo and icmp[icmptype] != icmp-echoreply
664
666 pcap(3PCAP)
667
669 Please send problems, bugs, questions, desirable enhancements, etc. to:
670 tcpdump-workers@lists.tcpdump.org
672 Filter expressions on fields other than those in Token Ring headers
674 will not correctly handle source-routed Token Ring packets.
675 Filter expressions on fields other than those in 802.11 headers will
677 not correctly handle 802.11 data packets with both To DS and From DS
678 set.
679 ip6 proto should chase header chain, but at this moment it does not.
681 ip6 protochain is supplied for this behavior.
682 Arithmetic expression against transport layer headers, like tcp[0],
684 does not work against IPv6 packets. It only looks at IPv4 packets.
685 6 January 2008 PCAP-FILTER(7)