multiping

multiping is a cli tool to monitor several targets at once using pings or tcp probing with optional logging of transition between states in a file.

Demo

Example with an unstable-server that flaps every 6s and a few other targets:

multiping localhost unstable-server tcp://google.com:80 tcp://[::1]:22

If you use a unix like shell, you can take advantage of shell's expansion for ranges like so:

multiping 192.168.0.{1..10}

Documentation

See multiping -h for detailed information.

Available probing means are:

• pure go ping (pro-bing, default)
• OS's ping command, via background process
• tcp (partial (S/SA/R tcp-shaker) or full handshake depending on the os)

ping

Pure Go is the default option but for unprivileged users (see linux notes), OS/system's ping command (usually available on OS with specific cap or setuid) can be used with a background spawn model with -s flag. Privileged mode (default when user is root or on windows) can be forcefully enabled with -privileged.

On pure Go implementation, ICMP packet size can be specified using -size option. Given size doesn't account for the 28 bytes header (note for usual limits: 1472 or 8972). This has no effect on system's ping, refer to system's manual and use -ping-options.

Hint ca be given about address family resolution using ip<family>://, ip:// is the default, ip4:// to force IPv4 and ip6:// to force IPv6, example:

• google.com is equivalent to ip://google.com
• ip4://google.com forces resolution of google.com as ipv4
• ip6://google.com forces resolution of google.com as ipv6

TCP probing

For tcp probing, on linux, freebsd and openbsd, S/SA/R pattern is used. This allows to probe tcp ports without really triggering an accept on the listening app. Issue is if a device in between perform syn poxing, the result might not reflect reality. On darwin and windows due to limitations, complete handshake is performed.

tcp probing example syntax:

• tcp://google.com:80
• tcp://192.168.0.1:443
• tcp://[::1]:22

As for ip://, tcp:// can also have hint of address family:

• tcp4://google.com:80 forces resolution of google.com as ipv4
• tcp6://google.com:80 forces resolution of google.com as ipv6

Transition logging

Transition logging can be enabled using -log filename. Log format is pretty self explanatory:

• Timestamp (string): timestamp
• UnixNano (int64): timestamp in nano seconds
• Host (string): the host provided as arg (inc. proto)
• Ip (string): the resolved host
• State (bool): true if alive, false if timeout
• Transition (string): "down to up" or "up to down"

Quiet mode

-q disable the refreshing output, might be useful in conjunction with -log.

Self update

Starting v1.2.0, multiping can self-update against github releases with -update flag

Linux notes on pure go ping

If run unprivileged, you might need to allow groups to perform "unprivileged" ping via UDP with the following sysctl:

sysctl -w net.ipv4.ping_group_range="0 2147483647"

You can also add net raw cap to the binary to use it with -privileged mode

cap_net_raw=+ep /path/to/your/compiled/binary

Source

Github repository: https://github.com/babs/multiping

libs used

• https://github.com/pterm/pterm
• https://github.com/prometheus-community/pro-bing
• https://github.com/tevino/tcp-shaker
• https://github.com/valyala/fastjson
• https://github.com/minio/selfupdate
• https://github.com/ulikunitz/xz