ping 8 iputils-&snapshot; ping, ping6 send ICMP ECHO_REQUEST to network hosts ping -aAbBdDfhLnOqrRUvV -c -F -i -I -l -m -M -N -w -W -p -Q -s -S -t -T Audible ping. Adaptive ping. Interpacket interval adapts to round-trip time, so that effectively not more than one (or more, if preload is set) unanswered probe is present in the network. Minimal interval is 200msec for not super-user. On networks with low rtt this mode is essentially equivalent to flood mode. Allow pinging a broadcast address. Do not allow -c Stop after sending option, Set the Print timestamp (unix time + microseconds as in gettimeofday) before each line. Flood ping. For every ECHO_REQUEST sent a period ``.'' is printed, while for ever ECHO_REPLY received a backspace is printed. This provides a rapid display of how many packets are being dropped. If interval is not given, it sets interval to zero and outputs packets as fast as they come back or one hundred times per second, whichever is more. Only the super-user may use this option with zero interval. -F Show help. -i Wait -I -l If Suppress loopback of multicast packets. This flag only applies if the ping destination is a multicast address. -m use -M Select Path MTU Discovery strategy. -N help Show help for NI support. name Queries for Node Names. ipv6 Queries for IPv6 Addresses. There are several IPv6 specific flags. ipv6-global Request IPv6 global-scope addresses. ipv6-sitelocal Request IPv6 site-local addresses. ipv6-linklocal Request IPv6 link-local addresses. ipv6-all Request IPv6 addresses on other interfaces. ipv4 Queries for IPv4 Addresses. There is one IPv4 specific flag. ipv4-all Request IPv4 addresses on other interfaces. subject-ipv6= IPv6 subject address. subject-ipv4= IPv4 subject address. subject-name= Subject name. If it contains more than one dot, fully-qualified domain name is assumed. subject-fqdn= Subject name. Fully-qualified domain name is always assumed. Numeric output only. No attempt will be made to lookup symbolic names for host addresses. Report outstanding ICMP ECHO reply before sending next packet. This is useful together with the timestamp -D to log output to a diagnostic file and search for missing answers. -p You may specify up to 16 ``pad'' bytes to fill out the packet you send. This is useful for diagnosing data-dependent problems in a network. For example, -p ff will cause the sent packet to be filled with all ones. Quiet output. Nothing is displayed except the summary lines at startup time and when finished. -Q Set Quality of Service -related bits in ICMP datagrams. In RFC2474, these fields are interpreted as 8-bit Differentiated Services (DS), consisting of: bits 0-1 (2 lowest bits) of separate data, and bits 2-7 (highest 6 bits) of Differentiated Services Codepoint (DSCP). In RFC2481 and RFC3168, bits 0-1 are used for ECN. Historically (RFC1349, obsoleted by RFC2474), these were interpreted as: bit 0 (lowest bit) for reserved (currently being redefined as congestion control), 1-4 for Type of Service and bits 5-7 (highest bits) for Precedence. Bypass the normal routing tables and send directly to a host on an attached interface. If the host is not on a directly-attached network, an error is returned. This option can be used to ping a local host through an interface that has no route through it provided the option -s Specifies the number of data bytes to be sent. The default is 56, which translates into 64 ICMP data bytes when combined with the 8 bytes of ICMP header data. -S Set socket sndbuf. If not specified, it is selected to buffer not more than one packet. -t -T Set special IP timestamp options. Print full user-to-user latency (the old behaviour). Normally Verbose output. Show version and exit. -w Specify a timeout, in seconds, before packet are sent, it waits either for expire or until probes are answered or for some error notification from network. -W Time to wait for a response, in seconds. The option affects only timeout in absence of any responses, otherwise When using If and are both specified, and fewer than packets are received by the time the has arrived, it will also exit with code 1. On other error it exits with code 2. Otherwise it exits with code 0. This makes it possible to use the exit code to see if a host is alive or not. This program is intended for use in network testing, measurement and management. Because of the load it can impose on the network, it is unwise to use An IP header without options is 20 bytes. An ICMP ECHO_REQUEST packet contains an additional 8 bytes worth of ICMP header followed by an arbitrary amount of data. When a If the data space is at least of size of Damaged packets are obviously serious cause for alarm and often indicate broken hardware somewhere in the The (inter)network layer should never treat packets differently depending on the data contained in the data portion. Unfortunately, data-dependent problems have been known to sneak into networks and remain undetected for long periods of time. In many cases the particular pattern that will have problems is something that doesn't have sufficient ``transitions'', such as all ones or all zeros, or a pattern right at the edge, such as almost all zeros. It isn't necessarily enough to specify a data pattern of all zeros (for example) on the command line because the pattern that is of interest is at the data link level, and the relationship between what you type and what the controllers transmit can be complicated. This means that if you have a data-dependent problem you will probably have to do a lot of testing to find it. If you are lucky, you may manage to find a file that either can't be sent across your network or that takes much longer to transfer than other similar length files. You can then examine this file for repeated patterns that you can test using the The TTL value of an IP packet represents the maximum number of IP routers that the packet can go through before being thrown away. In current practice you can expect each router in the Internet to decrement the TTL field by exactly one. The TCP/IP specification states that the TTL field for TCP packets should be set to 60, but many systems use smaller values (4.3 BSD uses 30, 4.2 used 15). The maximum possible value of this field is 255, and most Unix systems set the TTL field of ICMP ECHO_REQUEST packets to 255. This is why you will find you can ``ping'' some hosts, but not reach them with or . In normal operation ping prints the TTL value from the packet it receives. When a remote system receives a ping packet, it can do one of three things with the TTL field in its response: Not change it; this is what Berkeley Unix systems did before the 4.3BSD Tahoe release. In this case the TTL value in the received packet will be 255 minus the number of routers in the round-trip path. Set it to 255; this is what current Berkeley Unix systems do. In this case the TTL value in the received packet will be 255 minus the number of routers in the path Set it to some other value. Some machines use the same value for ICMP packets that they use for TCP packets, for example either 30 or 60. Others may use completely wild values. Many Hosts and Gateways ignore the RECORD_ROUTE option. The maximum IP header length is too small for options like RECORD_ROUTE to be completely useful. There's not much that can be done about this, however. Flood pinging is not recommended in general, and flood pinging the broadcast address should only be done under very controlled conditions. , . The The version described here is its descendant specific to Linux. http://www.skbuff.net/iputils/iputils-current.tar.bz2. Copyright (c) 1989 The Regents of the University of California. All rights reserved. This code is derived from software contributed to Berkeley by Mike Muuss. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. All advertising materials mentioning features or use of this software must display the following acknowledgement: This product includes software developed by the University of California, Berkeley and its contributors. 4. Neither the name of the University nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. ]]>