mping —
a simple multicast ping program
mping |
[ -6dhqrsv
]
[-c
COUNT
]
[-i
IFNAME
]
[-p
PORT
]
[-t
TTL
]
[-w
SEC
]
[-W
SEC
]
[GROUP ] |
mping aspires to be an easy to use and script
friendly program with support for both IPv4 and IPv6. Similar to the standard
ping(1) program, but
unlike it, the response to multicast ping is sent by another
mping. It can be used to verify intended
IGMP/MLD snooping functionality in any layer-2 bridges (switches), as well as
verify forwarding of multicast in static
(
SMCRoute) or dynamic
(
mrouted,
pimd,
pimd-dense, or
pim6sd) multicast routing setups.
By default,
mping starts in receiver mode,
joining group 225.1.2.3, and for each received UDP packet from the sender, it
is looped back. For unicast ping, this is handled by the TCP/IP stack. To run
in sender mode, use the
-s command line
option. Remember to adjust the TTL value if you are in a routed setup, and to
set the multicast interface with
-i
IFNAME, otherwise the unicast routing table
is used by the kernel to select the outbound interface, which often is not
what you want.
mping currently only supports any-source
multicast, ASM (*,G).
mping does not create or send IGMP/MLD frames
directly. Instead, it asks the kernel for groups from a specific interface,
which is then converted to the IGMPv2/MLDv1 join messages, or IGMPv3/MLDv2
membership reports by the kernel.
On Linux systems you can change the IGMP version of an interface, and thus what
type of packets the kernel generates, by writing to the file
/proc/sys/net/ipv4/conf/eth0/force_igmp_version.
E.g., to change
eth0 to IGMPv2:
echo 2 | sudo tee /proc/sys/net/ipv4/conf/eth0/force_igmp_version
-6- Use IPv6 instead of IPv4. Defaults to group ff2e::42, unless an IPv6
multicast grop is the first non-option argument. The optional group
argument overrides the address family, so if an IPv4 group is detected
this option is ignored
-c
COUNT- Stop sending/receiving after COUNT number of packets. The sender
mping has two modes of operation
available. The default is to exit after
COUNT number of packets have been sent.
The other mode is to wait for COUNT
packets to be recived. See -w option,
below, for more information.
-d- Enable debug messages.
-h- Print a summary of the options and exit
-i
IFNAME- Interface to use for sending/receiving multicast. The default is to
automatically look up the default interface from the unicast routing
table.
-p
PORT- UDP port number to send/listen to, default: 4321
-q- Quiet output, only startup message and summary lines are printed
-r- Act as receiver, looping back packets to the sender, default: yes
-s- Act as sender, sends packets to select groups, default: no
-t
TTL- TTL to use when sending multicast packets, default: 1
-v- Show version information
-w
DEADLINE- Timeout, in seconds, before exiting, waiting for
-c
COUNT replies. If
COUNT replies are received before the
deadline, mping exits.
-W
TIMEOUT- Timeout, in seconds, after the last received packet.
ping(1),
mcjoin(1),
nemesis(1)
Use the project's GitHub page to file bug reports, feature requests or patches
(preferably as GitHub pull requests), or questions at
⟨https://github.com/troglobit/mping⟩
Originally based on an example from the book Multicast Sockets, by David
Makofske and Kevin Almeroth. Since then completely rewritten and expanded on
by Joachim Wiberg at GitHub.