LADVD(8)

💖 LADVD — the ladvd(8) glow-up 💖

okay bestie, gather round, because this one is literally the main character of your managed switch's dreams. It lives in section 8 of the System Manager's Manual, and it's about to make your connected hosts visible. no cap.

✨ NAME ✨

ladvd — send link layer advertisements 🦋

🌸 SYNOPSIS 🌸

ladvd [ -a ] [ INTERFACE ] [ INTERFACE ] ...

💅 DESCRIPTION 💅

so ladvd sends LLDP (that's Link Layer Discovery Protocol, iykyk) advertisements on all available interfaces. the whole point? making connected hosts visible on managed switches. iconic behaviour, honestly.

by default it runs as a privilege-separated daemon — very demure, very security-conscious.

want more protocols in the mix? you can enable additional ones with the -C, -E, -F and -N options. slay.

and optionally you can hand it a list of interfaces it should utilize. but heads up, bestie: only physical or bond/bridge interfaces can be specified. vlan interfaces? nope, those can only be auto-detected. the way that vlan interfaces just cannot be named on the command line… 💀

🎀 INTERFACES 🎀

by default ladvd detects and uses all configured (UP) physical Ethernet interfaces. wireless interfaces? those stay quiet unless you pass the -w option. 🧚

on top of that, ladvd will recognize bundled interfaces (bridges, bonding) and use those to transmit additional information. so basically the result is: normally you should not need to specify interfaces on the ladvd command-line at all. the only reason to specify interfaces is to explicitly exclude a particular interface. that's it. that's the tea. 🍓

⭐ OPTIONS ⭐

• -a — auto-enable protocols based on received packets (this also enables receive mode).
• -d — dump pcap-compatible packets to stdout, which you can pipe to tcpdump (via | tcpdump -r -) or redirect to a file for further analysis. little forensic girlie moment.
• -e interface — exclude a particular interface. no packets will be transmitted on this interface. bye bestie 👋
• -f — run in the foreground and send logging to stderr.
• -h — print usage instructions.
• -m interface — the management interface for this host. addresses on this interface are auto-detected (IPv4 and IPv6).
• -n — use addresses of the management interface specified via -m for all interfaces.
• -o — run only once, useful for quick troubleshooting.
• -r — receive packets, and use them for various features.
• -s — be silent, don't transmit any packets. 🤫
• -q — use each interface's hwaddr to generate the chassis-id TLV. > not recommended, because the chassis-id should be the same for all interfaces. (like… pls don't, bestie.)
• -t — use Tun/Tap interfaces.
• -u user — switch to this user (defaults to ladvd).
• -v — increase logging verbosity.
• -w — use wireless interfaces.
• -y — save received peer hostname and port description in interface descriptions (requires SIOCSIFDESCR support) or Linux ifAliases. this also enables receive mode.
• -z — save received peer hostname and port name in interface descriptions (requires SIOCSIFDESCR support) or Linux ifAliases. this also enables receive mode.
• -c <CC> — specify a two-letter ISO 3166 country code (required for LLDP location support).
• -l <location> — specify the physical location of the host.
• -L — enable LLDP (Link Layer Discovery Protocol).
• -C — enable CDP (Cisco Discovery Protocol).
• -E — enable EDP (Extreme Discovery Protocol).
• -F — enable FDP (Foundry Discovery Protocol).
• -N — enable NDP (Nortel Discovery Protocol), formerly called SynOptics Network Management Protocol (SONMP).

👑 AUTHOR 👑

Sten Spans <sten@blinkenlights.nl> — the icon, the legend, the moment. 🫶

and that's the whole page, bestie. this beauty comes to you from the ladvd source, dated July 19, 2009, living its life as LADVD(8) in the System Manager's Manual. obsessed with her fr fr. 💜✨