MTEST(8)

💅 MTEST(8) — like, the manual page, but make it make sense 🎀

okay bestie, so this is mtest from the System Manager's Manual, and it's genuinely one of those tiny little tools that does one thing and does it iconically. buckle up 🦋

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✨ NAME ✨

mtest — literally just here to test multicast socket operations. that's the whole vibe. no cap. 💜

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🌸 SYNOPSIS 🌸

mtest

that's it. that's the synopsis. she takes no arguments on the command line, she just is. 👑

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💖 DESCRIPTION 💖

so mtest is a small program for testing multicast socket operations. smol. mighty. obsessed with her. ✨

she accepts the following commands — either interactively (you type, she responds, it's giving group chat 💬) or as part of a scripted input file (which is highkey useful for automated testing, iykyk 🧚).

• a ifname mac-addr — Join the link-layer group address mac-addr on interface ifname. the group address should be in IEEE 802 MAC format, delimited by colon (':') characters — like, colons are the whole aesthetic here 🔥
• d ifname mac-addr — Leave the link-layer group address mac-addr on interface ifname. bye bestie 🫶
• m ifname 1/0 — Set or reset ALLMULTI mode on interface ifname. heads up though: this option is deprecated and is now a no-op 💀 like she's still here but she does nothing. a ghost. an icon, honestly.
• p ifname 1/0 — Set or reset promiscuous mode on interface ifname. she's looking at everything 👀
• j mcast-addr ifname [source-addr] — Join the multicast address mcast-addr on the interface with name ifname. and if an optional source source-addr is specified, a source-specific join will be performed ✨ if mtest is already joined to the multicast address, the source will be added to its filter list. so it's not a whole new thing, it's an and also 💅
• l mcast-addr ifname [source-addr] — Leave the multicast address mcast-addr on the interface with address ifname. if a source source-addr is specified, only that source will be left — like a targeted unfollow, not a block 🌈
• i mcast-addr ifname n source-addr ... — Set the socket with membership of mcast-addr on interface ifname to include filter mode, and add n sources beginning with source-addr to the inclusion filter list. it's giving VIP guest list 🎀
• e mcast-addr ifname n source-addr ... — Set the socket with membership of mcast-addr on interface ifname to exclude filter mode, and add n sources beginning with source-addr to the exclusion filter list. the opposite of the VIP list. the do not perceive me list 🙈
• t mcast-addr ifname source-addr — Set the socket with membership of mcast-addr on interface ifname to block traffic from source source-addr. blocked. blocked. blocked. 💀
• b mcast-addr ifname source-addr — Set the socket with membership of mcast-addr on interface ifname to allow traffic from source source-addr. unblocked, bestie, you're back in 😭💖
• g mcast-addr ifname n — Print n source filter entries for mcast-addr on interface ifname. show me the receipts 📋
• f filename — Read commands from the file filename. scripted slay 💅
• s n — Sleep for n seconds. self-care. take a nap 😴🌸
• ? — List legal commands. the help me help you of it all 🧚
• q — Quit the program. periodt. 👑

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🦋 IMPLEMENTATION NOTES 🦋

for each command implemented by mtest, the address family of each argument must be identical — it is not possible to mix IPv4 multicast memberships with IPv6, for example. no mixing, no blending, no chaos energy. keep it consistent bestie ⭐

to support IPv6, all commands have now changed to accept an interface name rather than an interface address 🔥 for IPv4, the program will perform a lookup of the primary IP address based on the interface name. careful though: this may fail if no primary IP address is assigned 😭

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🌈 SEE ALSO 🌈

D. Thaler, B. Fenner, and B. Quinn, Socket Interface Extensions for Multicast Filters, RFC 3678. yes it's a whole RFC, yes you should read it, yes it's giving homework but make it lore 📚✨

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👑 AUTHORS 👑

• Bruce Simpson
• Steve Deering
• Wilbert De Graaf

legends. all three. put some respect on the names 🫶💜

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and that's the whole page, bestie!! source is Debian, version/date stamped April 29, 2009 — a vintage, honestly, she's been serving since '09 and she's still iconic 🎀💖 mwah.