1 <refentry id="ping"> 2 3 <refmeta> 4 <refentrytitle>ping</refentrytitle> 5 <manvolnum>8</manvolnum> 6 <refmiscinfo>iputils-&snapshot;</refmiscinfo> 7 </refmeta> 8 9 <refnamediv> 10 <refname>ping, ping6</refname> 11 <refpurpose>send ICMP ECHO_REQUEST to network hosts</refpurpose> 12 </refnamediv> 13 14 <refsynopsisdiv> 15 <cmdsynopsis> 16 <command>ping</command> 17 <arg choice="opt"><option>-aAbBdDfhLnOqrRUvV</option></arg> 18 <arg choice="opt">-c <replaceable/count/</arg> 19 <arg choice="opt">-F <replaceable/flowlabel/</arg> 20 <arg choice="opt">-i <replaceable/interval/</arg> 21 <arg choice="opt">-I <replaceable/interface/</arg> 22 <arg choice="opt">-l <replaceable/preload/</arg> 23 <arg choice="opt">-m <replaceable/mark/</arg> 24 <arg choice="opt">-M <replaceable/pmtudisc_option/</arg> 25 <arg choice="opt">-N <replaceable/nodeinfo_option/</arg> 26 <arg choice="opt">-w <replaceable/deadline/</arg> 27 <arg choice="opt">-W <replaceable/timeout/</arg> 28 <arg choice="opt">-p <replaceable/pattern/</arg> 29 <arg choice="opt">-Q <replaceable/tos/</arg> 30 <arg choice="opt">-s <replaceable/packetsize/</arg> 31 <arg choice="opt">-S <replaceable/sndbuf/</arg> 32 <arg choice="opt">-t <replaceable/ttl/</arg> 33 <arg choice="opt">-T <replaceable/timestamp option/</arg> 34 <arg choice="opt" rep="repeat"><replaceable/hop/</arg> 35 <arg choice="req"><replaceable/destination/</arg> 36 </cmdsynopsis> 37 </refsynopsisdiv> 38 39 <refsect1><title>DESCRIPTION</title> 40 <para> 41 <command/ping/ uses the ICMP protocol's mandatory ECHO_REQUEST 42 datagram to elicit an ICMP ECHO_RESPONSE from a host or gateway. 43 ECHO_REQUEST datagrams (``pings'') have an IP and ICMP 44 header, followed by a <structname/struct timeval/ and then an arbitrary 45 number of ``pad'' bytes used to fill out the packet. 46 </para> 47 <para> 48 <command/ping6/ is IPv6 version of <command/ping/, and can also send Node Information Queries (RFC4620). 49 Intermediate <replaceable/hop/s may not be allowed, because IPv6 source routing was deprecated (RFC5095). 50 </para> 51 </refsect1> 52 53 <refsect1><title>OPTIONS</title> 54 55 <variablelist> 56 <varlistentry> 57 <term><option/-a/</term> 58 <listitem><para> 59 Audible ping. 60 </para></listitem> 61 </varlistentry> 62 <varlistentry> 63 <term><option/-A/</term> 64 <listitem><para> 65 Adaptive ping. Interpacket interval adapts to round-trip time, so that 66 effectively not more than one (or more, if preload is set) unanswered probe 67 is present in the network. Minimal interval is 200msec for not super-user. 68 On networks with low rtt this mode is essentially equivalent to flood mode. 69 </para></listitem> 70 </varlistentry> 71 <varlistentry> 72 <term><option/-b/</term> 73 <listitem><para> 74 Allow pinging a broadcast address. 75 </para></listitem> 76 </varlistentry> 77 <varlistentry> 78 <term><option/-B/</term> 79 <listitem><para> 80 Do not allow <command/ping/ to change source address of probes. 81 The address is bound to one selected when <command/ping/ starts. 82 </para></listitem> 83 </varlistentry> 84 <varlistentry> 85 <term><option><anchor id="ping.count">-c <replaceable/count/</option></term> 86 <listitem><para> 87 Stop after sending <replaceable/count/ ECHO_REQUEST 88 packets. With 89 <link linkend="ping.deadline"><replaceable/deadline/</link> 90 option, <command/ping/ waits for 91 <replaceable/count/ ECHO_REPLY packets, until the timeout expires. 92 </para></listitem> 93 </varlistentry> 94 <varlistentry> 95 <term><option/-d/</term> 96 <listitem><para> 97 Set the <constant/SO_DEBUG/ option on the socket being used. 98 Essentially, this socket option is not used by Linux kernel. 99 </para></listitem> 100 </varlistentry> 101 <varlistentry> 102 <term><option/-D/</term> 103 <listitem><para> 104 Print timestamp (unix time + microseconds as in gettimeofday) before 105 each line. 106 </para></listitem> 107 </varlistentry> 108 <varlistentry> 109 <term><option/-f/</term> 110 <listitem><para> 111 Flood ping. For every ECHO_REQUEST sent a period ``.'' is printed, 112 while for ever ECHO_REPLY received a backspace is printed. 113 This provides a rapid display of how many packets are being dropped. 114 If interval is not given, it sets interval to zero and 115 outputs packets as fast as they come back or one hundred times per second, 116 whichever is more. 117 Only the super-user may use this option with zero interval. 118 </para></listitem> 119 </varlistentry> 120 <varlistentry> 121 <term><option>-F <replaceable/flow label/</option></term> 122 <listitem><para> 123 <command/ping6/ only. 124 Allocate and set 20 bit flow label (in hex) on echo request packets. 125 If value is zero, kernel allocates random flow label. 126 </para></listitem> 127 </varlistentry> 128 <varlistentry> 129 <term><option/-h/</term> 130 <listitem><para> 131 Show help. 132 </para></listitem> 133 </varlistentry> 134 <varlistentry> 135 <term><option>-i <replaceable/interval/</option></term> 136 <listitem><para> 137 Wait <replaceable/interval/ seconds between sending each packet. 138 The default is to wait for one second between each packet normally, 139 or not to wait in flood mode. Only super-user may set interval 140 to values less 0.2 seconds. 141 </para></listitem> 142 </varlistentry> 143 <varlistentry> 144 <term><option>-I <replaceable/interface/</option></term> 145 <listitem><para> 146 <replaceable/interface/ is either an address, or an interface name. 147 If <replaceable/interface/ is an address, it sets source address 148 to specified interface address. 149 If <replaceable/interface/ in an interface name, it sets 150 source interface to specified interface. 151 For <command/ping6/, when doing ping to a link-local scope 152 address, link specification (by the '%'-notation in 153 <replaceable/destination/, or by this option) is required. 154 </para></listitem> 155 </varlistentry> 156 <varlistentry> 157 <term><option>-l <replaceable/preload/</option></term> 158 <listitem><para> 159 If <replaceable/preload/ is specified, 160 <command/ping/ sends that many packets not waiting for reply. 161 Only the super-user may select preload more than 3. 162 </para></listitem> 163 </varlistentry> 164 <varlistentry> 165 <term><option/-L/</term> 166 <listitem><para> 167 Suppress loopback of multicast packets. This flag only applies if the ping 168 destination is a multicast address. 169 </para></listitem> 170 </varlistentry> 171 <varlistentry> 172 <term><option>-m <replaceable/mark/</option></term> 173 <listitem><para> 174 use <replaceable/mark/ to tag the packets going out. This is useful 175 for variety of reasons within the kernel such as using policy 176 routing to select specific outbound processing. 177 </para></listitem> 178 </varlistentry> 179 <varlistentry> 180 <term><option>-M <replaceable/pmtudisc_opt/</option></term> 181 <listitem><para> 182 Select Path MTU Discovery strategy. 183 <replaceable/pmtudisc_option/ may be either <replaceable/do/ 184 (prohibit fragmentation, even local one), 185 <replaceable/want/ (do PMTU discovery, fragment locally when packet size 186 is large), or <replaceable/dont/ (do not set DF flag). 187 </para></listitem> 188 </varlistentry> 189 <varlistentry> 190 <term><option>-N <replaceable/nodeinfo_option/</option></term> 191 <listitem><para> 192 <command/ping6/ only. 193 Send ICMPv6 Node Information Queries (RFC4620), instead of Echo Request. 194 <variablelist> 195 <varlistentry> 196 <term><option>help</option></term> 197 <listitem><para>Show help for NI support.</para></listitem> 198 </varlistentry> 199 </variablelist> 200 <variablelist> 201 <varlistentry> 202 <term><option>name</option></term> 203 <listitem><para>Queries for Node Names.</para></listitem> 204 </varlistentry> 205 </variablelist> 206 <variablelist> 207 <varlistentry> 208 <term><option>ipv6</option></term> 209 <listitem><para>Queries for IPv6 Addresses. There are several IPv6 specific flags. 210 <variablelist> 211 <varlistentry> 212 <term><option>ipv6-global</option></term> 213 <listitem><para>Request IPv6 global-scope addresses.</para></listitem> 214 </varlistentry> 215 </variablelist> 216 <variablelist> 217 <varlistentry> 218 <term><option>ipv6-sitelocal</option></term> 219 <listitem><para>Request IPv6 site-local addresses.</para></listitem> 220 </varlistentry> 221 </variablelist> 222 <variablelist> 223 <varlistentry> 224 <term><option>ipv6-linklocal</option></term> 225 <listitem><para>Request IPv6 link-local addresses.</para></listitem> 226 </varlistentry> 227 </variablelist> 228 <variablelist> 229 <varlistentry> 230 <term><option>ipv6-all</option></term> 231 <listitem><para>Request IPv6 addresses on other interfaces.</para></listitem> 232 </varlistentry> 233 </variablelist> 234 </para></listitem> 235 </varlistentry> 236 </variablelist> 237 <variablelist> 238 <varlistentry> 239 <term><option>ipv4</option></term> 240 <listitem><para>Queries for IPv4 Addresses. There is one IPv4 specific flag. 241 <variablelist> 242 <varlistentry> 243 <term><option>ipv4-all</option></term> 244 <listitem><para>Request IPv4 addresses on other interfaces.</para></listitem> 245 </varlistentry> 246 </variablelist> 247 </para></listitem> 248 </varlistentry> 249 </variablelist> 250 <variablelist> 251 <varlistentry> 252 <term><option>subject-ipv6=<replaceable/ipv6addr/</option></term> 253 <listitem><para>IPv6 subject address.</para></listitem> 254 </varlistentry> 255 </variablelist> 256 <variablelist> 257 <varlistentry> 258 <term><option>subject-ipv4=<replaceable/ipv4addr/</option></term> 259 <listitem><para>IPv4 subject address.</para></listitem> 260 </varlistentry> 261 </variablelist> 262 <variablelist> 263 <varlistentry> 264 <term><option>subject-name=<replaceable/nodename/</option></term> 265 <listitem><para>Subject name. If it contains more than one dot, 266 fully-qualified domain name is assumed.</para></listitem> 267 </varlistentry> 268 </variablelist> 269 <variablelist> 270 <varlistentry> 271 <term><option>subject-fqdn=<replaceable/nodename/</option></term> 272 <listitem><para>Subject name. Fully-qualified domain name is 273 always assumed.</para></listitem> 274 </varlistentry> 275 </variablelist> 276 </para></listitem> 277 </varlistentry> 278 <varlistentry> 279 <term><option/-n/</term> 280 <listitem><para> 281 Numeric output only. 282 No attempt will be made to lookup symbolic names for host addresses. 283 </para></listitem> 284 </varlistentry> 285 <varlistentry> 286 <term><option/-O/</term> 287 <listitem><para> 288 Report outstanding ICMP ECHO reply before sending next packet. 289 This is useful together with the timestamp <option>-D</option> to 290 log output to a diagnostic file and search for missing answers. 291 </para></listitem> 292 </varlistentry> 293 <varlistentry> 294 <term><option>-p <replaceable/pattern/</option></term> 295 <listitem><para> 296 You may specify up to 16 ``pad'' bytes to fill out the packet you send. 297 This is useful for diagnosing data-dependent problems in a network. 298 For example, <option>-p ff</option> will cause the sent packet 299 to be filled with all ones. 300 </para></listitem> 301 </varlistentry> 302 <varlistentry> 303 <term><option/-q/</term> 304 <listitem><para> 305 Quiet output. 306 Nothing is displayed except the summary lines at startup time and 307 when finished. 308 </para></listitem> 309 </varlistentry> 310 <varlistentry> 311 <term><option>-Q <replaceable/tos/</option></term> 312 <listitem><para> 313 Set Quality of Service -related bits in ICMP datagrams. 314 <replaceable/tos/ can be decimal (<command/ping/ only) or hex number. 315 </para> 316 <para> 317 In RFC2474, these fields are interpreted as 8-bit Differentiated 318 Services (DS), consisting of: bits 0-1 (2 lowest bits) of separate 319 data, and bits 2-7 (highest 6 bits) of Differentiated Services 320 Codepoint (DSCP). In RFC2481 and RFC3168, bits 0-1 are used for ECN. 321 </para> 322 <para> 323 Historically (RFC1349, obsoleted by RFC2474), these were interpreted 324 as: bit 0 (lowest bit) for reserved (currently being redefined as 325 congestion control), 1-4 for Type of Service and bits 5-7 326 (highest bits) for Precedence. 327 </para> 328 </listitem> 329 </varlistentry> 330 <varlistentry> 331 <term><option/-r/</term> 332 <listitem><para> 333 Bypass the normal routing tables and send directly to a host on an attached 334 interface. 335 If the host is not on a directly-attached network, an error is returned. 336 This option can be used to ping a local host through an interface 337 that has no route through it provided the option <option/-I/ is also 338 used. 339 </para></listitem> 340 </varlistentry> 341 <varlistentry> 342 <term><option/-R/</term> 343 <listitem><para> 344 <command/ping/ only. 345 Record route. 346 Includes the RECORD_ROUTE option in the ECHO_REQUEST 347 packet and displays the route buffer on returned packets. 348 Note that the IP header is only large enough for nine such routes. 349 Many hosts ignore or discard this option. 350 </para></listitem> 351 </varlistentry> 352 <varlistentry> 353 <term><option>-s <replaceable/packetsize/</option></term> 354 <listitem><para> 355 Specifies the number of data bytes to be sent. 356 The default is 56, which translates into 64 ICMP 357 data bytes when combined with the 8 bytes of ICMP header data. 358 </para></listitem> 359 </varlistentry> 360 <varlistentry> 361 <term><option>-S <replaceable/sndbuf/</option></term> 362 <listitem><para> 363 Set socket sndbuf. If not specified, it is selected to buffer 364 not more than one packet. 365 </para></listitem> 366 </varlistentry> 367 <varlistentry> 368 <term><option>-t <replaceable/ttl/</option></term> 369 <listitem><para> 370 <command/ping/ only. 371 Set the IP Time to Live. 372 </para></listitem> 373 </varlistentry> 374 <varlistentry> 375 <term><option>-T <replaceable/timestamp option/</option></term> 376 <listitem><para> 377 Set special IP timestamp options. 378 <replaceable/timestamp option/ may be either 379 <replaceable/tsonly/ (only timestamps), 380 <replaceable/tsandaddr/ (timestamps and addresses) or 381 <replaceable/tsprespec host1 [host2 [host3 [host4]]]/ 382 (timestamp prespecified hops). 383 </para></listitem> 384 </varlistentry> 385 <varlistentry> 386 <term><option/-U/</term> 387 <listitem><para> 388 Print full user-to-user latency (the old behaviour). Normally 389 <command/ping/ 390 prints network round trip time, which can be different 391 f.e. due to DNS failures. 392 </para></listitem> 393 </varlistentry> 394 <varlistentry> 395 <term><option/-v/</term> 396 <listitem><para> 397 Verbose output. 398 </para></listitem> 399 </varlistentry> 400 <varlistentry> 401 <term><option/-V/</term> 402 <listitem><para> 403 Show version and exit. 404 </para></listitem> 405 </varlistentry> 406 <varlistentry> 407 <term><option><anchor id="ping.deadline">-w <replaceable/deadline/</option></term> 408 <listitem><para> 409 Specify a timeout, in seconds, before 410 <command/ping/ 411 exits regardless of how many 412 packets have been sent or received. In this case 413 <command/ping/ 414 does not stop after 415 <link linkend="ping.count"><replaceable/count/</link> 416 packet are sent, it waits either for 417 <link linkend="ping.deadline"><replaceable/deadline/</link> 418 expire or until 419 <link linkend="ping.count"><replaceable/count/</link> 420 probes are answered or for some error notification from network. 421 </para></listitem> 422 </varlistentry> 423 <varlistentry> 424 <term><option>-W <replaceable/timeout/</option></term> 425 <listitem><para> 426 Time to wait for a response, in seconds. The option affects only timeout 427 in absence of any responses, otherwise <command/ping/ waits for two RTTs. 428 </para></listitem> 429 </varlistentry> 430 </variablelist> 431 432 <para> 433 When using <command/ping/ for fault isolation, it should first be run 434 on the local host, to verify that the local network interface is up 435 and running. Then, hosts and gateways further and further away should be 436 ``pinged''. Round-trip times and packet loss statistics are computed. 437 If duplicate packets are received, they are not included in the packet 438 loss calculation, although the round trip time of these packets is used 439 in calculating the minimum/average/maximum round-trip time numbers. 440 When the specified number of packets have been sent (and received) or 441 if the program is terminated with a 442 <constant/SIGINT/, a brief summary is displayed. Shorter current statistics 443 can be obtained without termination of process with signal 444 <constant/SIGQUIT/. 445 </para> 446 447 <para> 448 If <command/ping/ does not receive any reply packets at all it will 449 exit with code 1. If a packet 450 <link linkend="ping.count"><replaceable/count/</link> 451 and 452 <link linkend="ping.deadline"><replaceable/deadline/</link> 453 are both specified, and fewer than 454 <link linkend="ping.count"><replaceable/count/</link> 455 packets are received by the time the 456 <link linkend="ping.deadline"><replaceable/deadline/</link> 457 has arrived, it will also exit with code 1. 458 On other error it exits with code 2. Otherwise it exits with code 0. This 459 makes it possible to use the exit code to see if a host is alive or 460 not. 461 </para> 462 463 464 <para> 465 This program is intended for use in network testing, measurement and 466 management. 467 Because of the load it can impose on the network, it is unwise to use 468 <command/ping/ during normal operations or from automated scripts. 469 </para> 470 471 </refsect1> 472 473 474 <refsect1><title>ICMP PACKET DETAILS</title> 475 476 <para> 477 An IP header without options is 20 bytes. 478 An ICMP ECHO_REQUEST packet contains an additional 8 bytes worth 479 of ICMP header followed by an arbitrary amount of data. 480 When a <replaceable/packetsize/ is given, this indicated the size of this 481 extra piece of data (the default is 56). Thus the amount of data received 482 inside of an IP packet of type ICMP ECHO_REPLY will always be 8 bytes 483 more than the requested data space (the ICMP header). 484 </para> 485 486 <para> 487 If the data space is at least of size of <structname/struct timeval/ 488 <command/ping/ uses the beginning bytes of this space to include 489 a timestamp which it uses in the computation of round trip times. 490 If the data space is shorter, no round trip times are given. 491 </para> 492 493 </refsect1> 494 495 <refsect1><title>DUPLICATE AND DAMAGED PACKETS</title> 496 497 <para> 498 <command/ping/ will report duplicate and damaged packets. 499 Duplicate packets should never occur, and seem to be caused by 500 inappropriate link-level retransmissions. 501 Duplicates may occur in many situations and are rarely (if ever) a 502 good sign, although the presence of low levels of duplicates may not 503 always be cause for alarm. 504 </para> 505 506 <para> 507 Damaged packets are obviously serious cause for alarm and often 508 indicate broken hardware somewhere in the 509 <command/ping/ packet's path (in the network or in the hosts). 510 </para> 511 512 </refsect1> 513 514 <refsect1><title>TRYING DIFFERENT DATA PATTERNS</title> 515 516 <para> 517 The (inter)network layer should never treat packets differently depending 518 on the data contained in the data portion. 519 Unfortunately, data-dependent problems have been known to sneak into 520 networks and remain undetected for long periods of time. 521 In many cases the particular pattern that will have problems is something 522 that doesn't have sufficient ``transitions'', such as all ones or all 523 zeros, or a pattern right at the edge, such as almost all zeros. 524 It isn't necessarily enough to specify a data pattern of all zeros (for 525 example) on the command line because the pattern that is of interest is 526 at the data link level, and the relationship between what you type and 527 what the controllers transmit can be complicated. 528 </para> 529 530 <para> 531 This means that if you have a data-dependent problem you will probably 532 have to do a lot of testing to find it. 533 If you are lucky, you may manage to find a file that either can't be sent 534 across your network or that takes much longer to transfer than other 535 similar length files. 536 You can then examine this file for repeated patterns that you can test 537 using the <option/-p/ option of <command/ping/. 538 </para> 539 540 </refsect1> 541 542 <refsect1><title>TTL DETAILS</title> 543 544 <para> 545 The TTL value of an IP packet represents the maximum number of IP routers 546 that the packet can go through before being thrown away. 547 In current practice you can expect each router in the Internet to decrement 548 the TTL field by exactly one. 549 </para> 550 551 <para> 552 The TCP/IP specification states that the TTL field for TCP 553 packets should be set to 60, but many systems use smaller values 554 (4.3 BSD uses 30, 4.2 used 15). 555 </para> 556 557 <para> 558 The maximum possible value of this field is 255, and most Unix systems set 559 the TTL field of ICMP ECHO_REQUEST packets to 255. 560 This is why you will find you can ``ping'' some hosts, but not reach them 561 with 562 <citerefentry><refentrytitle/telnet/<manvolnum/1/</citerefentry> 563 or 564 <citerefentry><refentrytitle/ftp/<manvolnum/1/</citerefentry>. 565 </para> 566 567 <para> 568 In normal operation ping prints the TTL value from the packet it receives. 569 When a remote system receives a ping packet, it can do one of three things 570 with the TTL field in its response: 571 </para> 572 573 <itemizedlist> 574 <listitem><para> 575 Not change it; this is what Berkeley Unix systems did before the 576 4.3BSD Tahoe release. In this case the TTL value in the received packet 577 will be 255 minus the number of routers in the round-trip path. 578 </para></listitem> 579 <listitem><para> 580 Set it to 255; this is what current Berkeley Unix systems do. 581 In this case the TTL value in the received packet will be 255 minus the 582 number of routers in the path <emphasis/from/ 583 the remote system <emphasis/to/ the <command/ping/ing host. 584 </para></listitem> 585 <listitem><para> 586 Set it to some other value. Some machines use the same value for 587 ICMP packets that they use for TCP packets, for example either 30 or 60. 588 Others may use completely wild values. 589 </para></listitem> 590 </itemizedlist> 591 592 </refsect1> 593 594 <refsect1><title>BUGS</title> 595 596 <itemizedlist> 597 <listitem><para> 598 Many Hosts and Gateways ignore the RECORD_ROUTE option. 599 </para></listitem> 600 <listitem><para> 601 The maximum IP header length is too small for options like 602 RECORD_ROUTE to be completely useful. 603 There's not much that can be done about this, however. 604 </para></listitem> 605 <listitem><para> 606 Flood pinging is not recommended in general, and flood pinging the 607 broadcast address should only be done under very controlled conditions. 608 </para></listitem> 609 </itemizedlist> 610 611 </refsect1> 612 613 <refsect1><title>SEE ALSO</title> 614 <para> 615 <citerefentry><refentrytitle/netstat/<manvolnum/1/</citerefentry>, 616 <citerefentry><refentrytitle/ifconfig/<manvolnum/8/</citerefentry>. 617 </para> 618 </refsect1> 619 620 <refsect1><title>HISTORY</title> 621 <para> 622 The <command/ping/ command appeared in 4.3BSD. 623 </para> 624 <para> 625 The version described here is its descendant specific to Linux. 626 </para> 627 </refsect1> 628 629 <refsect1><title>SECURITY</title> 630 <para> 631 <command/ping/ requires <constant/CAP_NET_RAW/ capability 632 to be executed. It may be used as set-uid root. 633 </para> 634 </refsect1> 635 636 <refsect1><title>AVAILABILITY</title> 637 <para> 638 <command/ping/ is part of <filename/iputils/ package 639 and the latest versions are available in source form at 640 <ulink url="http://www.skbuff.net/iputils/iputils-current.tar.bz2"> 641 http://www.skbuff.net/iputils/iputils-current.tar.bz2</ulink>. 642 </para> 643 </refsect1> 644 645 <![IGNORE[ 646 <refsect1><title>COPYING</title> 647 <para> 648 <literallayout> 649 Copyright (c) 1989 The Regents of the University of California. 650 All rights reserved. 651 652 This code is derived from software contributed to Berkeley by 653 Mike Muuss. 654 655 Redistribution and use in source and binary forms, with or without 656 modification, are permitted provided that the following conditions 657 are met: 658 1. Redistributions of source code must retain the above copyright 659 notice, this list of conditions and the following disclaimer. 660 2. Redistributions in binary form must reproduce the above copyright 661 notice, this list of conditions and the following disclaimer in the 662 documentation and/or other materials provided with the distribution. 663 3. All advertising materials mentioning features or use of this software 664 must display the following acknowledgement: 665 This product includes software developed by the University of 666 California, Berkeley and its contributors. 667 4. Neither the name of the University nor the names of its contributors 668 may be used to endorse or promote products derived from this software 669 without specific prior written permission. 670 671 THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 672 ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 673 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 674 ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 675 FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 676 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 677 OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 678 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 679 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 680 OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 681 SUCH DAMAGE. 682 </literallayout> 683 </para> 684 </refsect1> 685 ]]> 686 687 688 </refentry> 689 690
