Linux Command – ping ใช้ในการตรวจสอบสถานะ server ปลายทาง
ping <IP/Domain name>
$ ping google.com PING google.com (22.214.171.124) 56(84) bytes of data. 64 bytes from kul06s14-in-f206.1e100.net (126.96.36.199): icmp_seq=1 ttl=52 time=29.9 ms 64 bytes from kul06s14-in-f206.1e100.net (188.8.131.52): icmp_seq=2 ttl=52 time=30.5 ms 64 bytes from kul06s14-in-f206.1e100.net (184.108.40.206): icmp_seq=3 ttl=52 time=30.9 ms
ping [-aAbBdDfhLnOqrRUvV] [-c count] [-F flowlabel] [-i interval] [-I interface] [-l preload] [-m mark] [-M pmtudisc_option] [-N nodeinfo_option] [-w deadline] [-W timeout] [-p pattern] [-Q tos] [-s packetsize] [-S sndbuf] [-t ttl] [-T timestamp option] [hop ...] destination
เป็นคำสั่งที่ใช้ในการตรวจสอบสถานะ server ปลายทาง โดยทำการส่งสัญญาณ ICMP ECHO_REQUEST ผ่าน network ไปยังปลายทาง ถ้าสถานะปกติ ได้รับสัญญาณตอบกลับมา ใช้ในการตรวจสอบ connection, ip ,port และ response time ของ server ปลายทางว่าปกติไหม
-a Audible ping. -A 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. -b Allow pinging a broadcast address. -B Do not allow ping to change source address of probes. The address is bound to one selected when ping starts. -c count Stop after sending count ECHO_REQUEST packets. With deadline option, ping waits for count ECHO_REPLY packets, until the timeout expires. -d Set the SO_DEBUG option on the socket being used. Essentially, this socket option is not used by Linux kernel. -D Print timestamp (unix time + microseconds as in gettimeofday) before each line. -f 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 flow label ping6 only. Allocate and set 20 bit flow label (in hex) on echo request packets. If value is zero, kernel allocates random flow label. -h Show help. -i interval Wait interval seconds between sending each packet. The default is to wait for one second between each packet normally, or not to wait in flood mode. Only super-user may set interval to values less 0.2 seconds. -I interface interface is either an address, or an interface name. If interface is an address, it sets source address to specified interface address. If interface in an interface name, it sets source interface to specified interface. For ping6, when doing ping to a link-local scope address, link specification (by the '%'-notation in destination, or by this option) is required. -l preload If preload is specified, ping sends that many packets not waiting for reply. Only the super-user may select preload more than 3. -L Suppress loopback of multicast packets. This flag only applies if the ping destination is a multicast address. -m mark use mark to tag the packets going out. This is useful for variety of reasons within the kernel such as using policy routing to select specific outbound processing. -M pmtudisc_opt Select Path MTU Discovery strategy. pmtudisc_option may be either do (prohibit fragmentation, even local one), want (do PMTU discovery, fragment locally when packet size is large), or dont (do not set DF flag). -N nodeinfo_option ping6 only. Send ICMPv6 Node Information Queries (RFC4620), instead of Echo Request. 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=ipv6addr IPv6 subject address. subject-ipv4=ipv4addr IPv4 subject address. subject-name=nodename Subject name. If it contains more than one dot, fully-qualified domain name is assumed. subject-fqdn=nodename Subject name. Fully-qualified domain name is always assumed. -n Numeric output only. No attempt will be made to lookup symbolic names for host addresses. -O 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 pattern 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. -q Quiet output. Nothing is displayed except the summary lines at startup time and when finished. -Q tos Set Quality of Service -related bits in ICMP datagrams. tos can be decimal (ping only) or hex number. 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. -r 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 -I is also used. -R ping only. Record route. Includes the RECORD_ROUTE option in the ECHO_REQUEST packet and displays the route buffer on returned packets. Note that the IP header is only large enough for nine such routes. Many hosts ignore or discard this option. -s packetsize 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 sndbuf Set socket sndbuf. If not specified, it is selected to buffer not more than one packet. -t ttl ping only. Set the IP Time to Live. -T timestamp option Set special IP timestamp options. timestamp option may be either tsonly (only timestamps), tsandaddr (timestamps and addresses) or tsprespec host1 [host2 [host3 [host4]]] (timestamp prespecified hops). -U Print full user-to-user latency (the old behaviour). Normally ping prints network round trip time, which can be different f.e. due to DNS failures. -v Verbose output. -V Show version and exit. -w deadline Specify a timeout, in seconds, before ping exits regardless of how many packets have been sent or received. In this case ping does not stop after count packet are sent, it waits either for deadline expire or until count probes are answered or for some error notification from network. -W timeout Time to wait for a response, in seconds. The option affects only timeout in absence of any responses, otherwise ping waits for two RTTs.
Author: Suphakit Annoppornchai