mcfirst(1)

💖 mcfirst(1) — the check-if-you-can-get-multicast bestie 💖

okay so real talk, this is a page from the General Commands Manual (the User Manuals section, to be exact), and it's about a lil tool called mcfirst 🦋

✨ NAME ✨

mcfirst — check if you can receive IPv4/IPv6 multicast 💅

🌸 SYNOPSIS 🌸

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

🎀 DESCRIPTION 🎀

so basically, mcfirst is the vibe check for your multicast setup — you use it to figure out whether you can actually receive multicast packets from some host. and the host can be sending literally any kind of multicast packets, from any application, IPv4 or IPv6, ASM or SSM. no gatekeeping here 💖

what it does is join the specified source (if you gave one) and group, and then it just... listens on the specified port 👂

by default it dips out the second the first packet shows up, and prints how long it waited. it's giving patient but not that patient energy fr fr ✨

💅 OPTIONS 💅

the options are as follows, bestie:

• -4 — force IPv4, no negotiations 🫶
• -6 — force IPv6, periodt 👑
• -v — print version (the receipts, the lore)
• -r — print rate information only, that's it, that's the whole post
• -I interface — the interface to join on 🦋
• -c count — stop after receiving count packets. default is 1, unless a time limit is specified
• -t time — exit after time seconds. default is to exit after the first packet. and if you specify both count and time, mcfirst will exit as soon as one of them is satisfied — whichever hits first wins, no cap 😭

🌈 SEE ALSO 🌈

• ssmping(1) — a tool for checking whether can receive SSM.
• dbeacon(1) — a distributed beacon multicast implementation.

💀 BUGS 💀

found a bug? please report them to Stig Venaas <venaas@uninett.no>, the author of this tool 🙈 (yes, we're sending bug reports to the actual author, that's just how it is)

⭐ HISTORY ⭐

mcfirst was developed by Stig Venaas during the early days of the m6bone, the IPv6 multicast backbone. iconic origin story honestly 🧚

and that's the whole page bestie!! this came out of the User Manuals section, mcfirst(1) — go forth and vibe check your multicast 💜💖✨