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OMPING(8) System Manager's Manual OMPING(8) NAME omping -- test IP multicast SYNOPSIS omping [-46CDEFqVv] [-c count] [-i interval] [-M transport_method] [-m mcast_addr] [-O op_mode] [-p port] [-R rcvbuf] [-r rate_limit] [-S sndbuf] [-T timeout] [-t ttl] [-w wait_time] remote_addr... DESCRIPTION The omping is program which uses User Datagram Protocol to determine if computer is able to send and/or receive IP unicast and multicast or Broadcast packets from the network. It's designed to be used in very similar way as ping(8) and also has some features of the fping(8) com- mand. Where ping(8) and omping differ is in who replies. In ping(8) replies are sent by the operating system and with omping another in- stance of omping sends the reply. This mean that omping must be running on all computers to test sending/receiving IP multicast/broadcast. Its arguments are as follows: -4 Force usage of IPv4. -6 Force usage of IPv6. -C Display continuous statistics for every reply message. -D Disable packet duplicate detection. Option is default for in- terval 0. -E Default behaviour when every client is in stop state is to exit. This may happen if all server sends stop message or if count query messages was sent. This option changes default be- haviour and omping doesn't quit automatically. -F Allow entering of arguments which are not allowed or not recom- mended by the specification. This is typically the interval pa- rameter. This option may be used multiple times. -q Quiet output. Nothing is displayed except state changes and summary. Option can be used twice and then only summary is dis- played. -V Display version and quit. Option can be used twice and then re- mote version is displayed. -v Set level of verbosity. Parameter can be used multiple times to achieve higher verbosity. -c count Number of request packets to send to each target. After sending count query messages, given client is put to stop state and it is no longer sending query messages. -i interval Wait interval seconds between sending each request packet. Float values are supported in millisecond precision. It's pos- sible to set there 0 with meaning that packets are sent ether after previous unicast reply is received or after 1 millisec- ond, depending on which of these intervals is smaller. The de- fault is to wait for one second between each packet. -M transport_method Set transport method to use. This can be asm for Any-source Multicast, ssm for Source-specific Multicast and ipbc for IP Broadcast. -m mcast_addr Multicast or broadcast address to listen on for multi- cast/broadcast answer messages. Default is 232.43.211.234 for IPv4 and ff3e::4321:1234 for IPv6 multicast, or broadcast ad- dress of local interface for Broadcast. -O op_mode omping can be running in three different modes. Default and recommended mode for quick testing is normal mode, when omping behaves like client and server together. It sends queries and is able to respond them. Finally the client mode sends queries, but never respond to other nodes. -p port Port to bind and listen on for both unicast and multi- cast/broadcast messages. Default is 4321. -R rcvbuf Set socket rcvbuf. Minimum value for this option is 2048. If not specified, rcvbuf is not changed and default OS provided value is used. -r rate_limit Rate limit interval between two query messages to rate_limit seconds. Default value is same as interval given by -i option. Rate limiting can be disabled by specifying 0 as value. Rate limiting is by default disabled for -i with 0 seconds. -S sndbuf Set socket sndbuf. Minimum value for this option is 2048. If not specified, sndbuf is not changed and default OS provided value is used. -T timeout Specify a timeout, in seconds, before omping exits regardless of how many packets have been received. -t ttl Time-To-Live of sent packets. -w wait_time after omping is stopped (by sending SIGINT or timeout expire) it is moved to special state when no queries are made and server answer all queries by server response (stop message). This makes possible to give correct (unbiased) result of lost packets on other nodes. Default is 3 times interval or 1 sec- ond, depending which one is larger. Also special value 0 can be used to not wait at all or -1 which means wait forever (this can be still terminated by sending SIGINT). remote_addr List of addresses to test. One of them must be address of local internet interface. This local address is used for bind and listening on for unicast packets. It's also used to determine which interface should be used for sending multicast/broadcast replies. Program is normally terminated by SIGINT. After signal receive summary is displayed. You can also display summary during running by sending SIGINFO or SIGUSR1 signal. When using omping for fault isolation, it should first be run against local internet interface only, to verify that the local network inter- face is up and running, and firewall is correctly configured. This mode is available by entering only local IP address. EXIT STATUS The omping utility exits 0 on success, and >0 if an error occurs. EXAMPLES The following commands and output is a typical way how to find-out and solve network problems using omping. In this situation, we have 3 com- puters named node-01, node-02 and node-03 with IP addresses 192.168.1.101 - 192.168.1.103. Let's run the following command on all of them. $ omping node-01 node-02 node-03 on all of nodes we should be able to seen similar output node-01: waiting for response msg node-03: waiting for response msg node-01: joined (S,G) = (*, 232.43.211.234), pinging node-03: joined (S,G) = (*, 232.43.211.234), pinging node-01: unicast, seq=1, size=69 bytes, dist=0, time=0.192ms node-01: multicast, seq=1, size=69 bytes, dist=0, time=0.284ms node-03: unicast, seq=1, size=69 bytes, dist=0, time=0.279ms node-03: multicast, seq=1, size=69 bytes, dist=0, time=0.360ms The first two lines tell us, that node-02 (actual node) is waiting for a response message from node-01 and node-03. The second two lines con- tain information, that we were successfully able to send an init mes- sage and also received a response message from remote nodes. Both of these messages are unicast, so we are able to send and receive unicast messages on a given port. If all of nodes are up and omping is running on all of them, but we are not able to receive a response message, it's time to check connectivity between nodes. First make sure that you are able to ping(8) them. If so, make sure that your firewall allows port 4321 to receive udp packets. The next line tells us that we were able to receive a 69 byte unicast response message from node-01, with a sequence number of 1. The dis- tance between the computers is 0 so they are on the same link net. Time between send and receive packet was 0.192 ms, that is also the current average time and lastly there were no lost packets. The 6th line tells us the same information as the previous one, but the received message is a multicast message. It means, that multicast is probably well configured. The 7th and 8th lines are same as previous two one but for node-03. If the node is able to receive unicast packets, but never multicast, it means that multicast configuration is incorrect. It's recommended to turn off your firewall. If multicast packets start to arrive, great. If not, the problem is hidden in the switches/routers between the nodes. Contact your system administrator to allow multicast traffic on the switch or router. omping is terminated by SIGINT signal (CTRL-c). Summary statistics are shown node-01: unicast, xmt/rcv/%loss = 18/18/0%, min/avg/max/std-dev = 0.177/0.301/0.463/0.073 node-01: multicast, xmt/rcv/%loss = 18/18/0%, min/avg/max/std-dev = 0.193/0.335/0.547/0.090 node-03: unicast, xmt/rcv/%loss = 21/21/0%, min/avg/max/std-dev = 0.272/0.299/0.327/0.017 node-03: multicast, xmt/rcv/%loss = 21/20/4% (seq>=2 0%), min/avg/max/std-dev = 0.347/0.388/0.575/0.055 Last line has additional information (seq>=2 %0) which means, that af- ter receiving first multicast packet with seq number 2, no other multi- cast packet was lost. Because creating multicast tree is time consum- ing, it's pretty normal to lost first few multicast packets. rcv field can also be formatted like node-01: unicast, xmt/rcv/%loss = 3/3+1/0%, min/avg/max/std-dev = 0.294/0.299/0.305/0.006 This means, that 1 duplicate packet was received. It's possible to find out duplicate packet by looking to output and find line which has fol- lowing format node-01: unicast, seq=2 (dup), size=69 bytes, dist=0, time=0.469ms SEE ALSO fping(8), ping(8) STANDARDS omping uses Internet-Draft draft-ietf-mboned-ssmping-08 as underlaying protocol and tries to be as compliant as possible. AUTHORS The omping utility was written by Jan Friesse <jfriesse@redhat.com>. BUGS - Some OSes may not have support for receiving TTL from packet. omping then cannot provide distance information. - Some OSes may not provide information about packet receive. Less precise actual time is then used. - omping highly depends on precise poll(2) and gettimeofday(3) func- tions. If OS doesn't provide at least milliseconds precision, re- sults may be incorrect. FreeBSD ports 15.0 Jun 22, 2011 OMPING(8)
NAME | SYNOPSIS | DESCRIPTION | EXIT STATUS | EXAMPLES | SEE ALSO | STANDARDS | AUTHORS | BUGS
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