---
name: "mcfirst"
section: "1"
platform: "linux"
package: "ssmping"
version: "0.9.1-4"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/mcfirst"
---

# mcfirst(1)

check if you can receive IPv4/IPv6 multicast

## NAME

mcfirst - check if you can receive IPv4/IPv6 multicast

## SYNOPSIS

**mcfirst** \[ **-46vr** \] \[ **-I** *interface* \] \[ **-c** *count* \] \[ **-t** *time* \] \[ *source* \] *group* *port*

## DESCRIPTION

**mcfirst** can be used to check whether one can receive multicast packets from a host. The host may send any type of multicast packets, any application, IPv4 or IPv6, ASM or SSM. **mcfirst** joins the specified (source) and group, and listens to the specified port. **mcfirst will by default exit when the first packet is received, and print how long it waited.**

## OPTIONS

The options are as follows.

- **-4**

  Force IPv4

- **-6**

  Force IPv6

- **-v**

  Print version

- **-r**

  Print rate information only

- **-I** *interface*

  Interface to join on

- **-c** *count*

  Stop after receiving *count* packets. Default is 1 unless time limit is specified

- **-t** *time*

  Exit after *time* seconds. Default is to exit after the first packet. If both *count* and *time* are specified, mcfirst will exit as soon as one of them is satisfied.

## SEE ALSO

[ssmping(1)](/ssmping/1.md) a tool for checking whether can receive SSM.

- [dbeacon(1)](/dbeacon/1.md) a distributed beacon multicast implementation.

  ## BUGS

Please report them to Stig Venaas \<venaas@uninett.no\>, the author of this tool.

## HISTORY

**mcfirst** was developed by Stig Venaas during the early days of the m6bone, the IPv6 multicast backbone.