ATMARPD(8)

💖 ATMARPD 💖 — like, the ATMARP daemon bestie (section 8, maintenance commands, iykyk)

okay so first things first, bestie: this whole page lives in the Maintenance Commands part of the manual, and it's atmarpd we're talking about. Sit down, grab a boba, we're doing ATMARP together 🫶

✨ NAME ✨

atmarpd — the ATMARP demon (yes it says demon, that's the vibe, it's giving iconic typo energy and we're keeping it fr fr) 😈💅

✨ SYNOPSIS ✨

atmarpd [-b] [-d] [-D directory] [-l logfile] [-m] [-n]
atmarpd -V

✨ DESCRIPTION ✨

so atmarpd is the whole implementation of the ATMARP protocol, exactly as specified in RFC1577 and RFC1755. no cap. 🌈

here's the tea: address resolution requests get sent from the kernel (using a comparably simple protocol, lowkey easy) over to the ATMARP demon, and then the demon is the one doing the whole dialog with the network. it's the main character, truly. 👑

and it's flexible like that — atmarpd can operate as an ATMARP client and as an ATMARP server. it also supports the concurrent use of several IP over ATM interfaces, because why pick one when you can have them all. 💅

atmarpd is configured from the command line using the atmarp program. and unless debugging is enabled, the ATMARP table gets written after every change to the file /var/run/atmarpd.table — or to a file with the same name in a different directory, if you're using the -D option. ✨

heads up bestie: atmarpd disables support for SVCs if signaling is not available at start time — i.e. if atmsigd is not running. so if your SVCs are missing, that's why, don't come for me 😭

✨ OPTIONS ✨

• -b — run in background (i.e. in a forked child process) after initializing. it goes off and does its thing, no attention needed 🦋
• -d — enables (lots of) debugging output. by default, atmarpd is comparably quiet — this is the "not me turning the volume ALL the way up" flag 🔊
• -D dump_dir — changes the directory where atmarpd writes its table (atmarpd.table). by default, /var/run is used. moving day, but for a file 📁
• -l logfile — write diagnostic messages to the specified file instead of to standard error. the special name syslog is used to send diagnostics to the system logger. (yes, literally the word syslog, that's the magic word 🪄)
• -m — enables merging of incoming calls if the address is known. here's what that means: an incoming connection on which no InARP reply has been received yet, but which originates from an ATM address for which an ATMARP entry already exists, is automatically added to that entry. this assumes that there is a 1:1 mapping between IP addresses and ATMARP addresses. by default, this assumption is not made — which frequently results in the setup of duplicate connections. 💀

okay real talk, this one matters: RFC1577 requires that an ATMARP server sends an InARP request on an incoming connection. Merging may therefore violate RFC1577 in this case. so like... know what you're doing, bestie 🙈

• -n — prints addresses in numeric format only, i.e. no address to name translation is attempted. just numbers, no names, keep it simple ✨
• -V — prints the version number of atmarpd on standard output and exits. the little "hi, this is me" flag 🎀

✨ FILES ✨

• /var/run/atmarpd.table — the ATMARP table 📋
• /proc/atm/arp — table of currently active IP over ATM VCs 🌸

✨ BUGS ✨

so there's this one thing: atmarpd removes ATMARP entries from the kernel table while refreshing them. that's just... what it does. it's a documented quirk, not a vibe, but we live 💀

✨ AUTHOR ✨

Werner Almesberger, EPFL ICA <werner.almesberger@epfl.ch> — thank you king, we appreciate you 🫶👑

✨ SEE ALSO ✨

atmarp(8), atmsigd(8) — go read those too, bestie, they're part of the lore 🦋

and that's the whole page!! mwah 💋 this one's from the Linux distribution, dated April 26, 2000 — yes, a year-2000 icon, aging like fine wine, periodt. 🍓✨