TUNCTL(8)

💅 tunctl(8) — like, the manual page, bestie

okay so this is tunctl, and it lives in section 8 of the manual (that's the sysadmin-y one, iykyk). she's a little tool with one job and she does it impeccably. let's get into it 🫶

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✨ NAME ✨

tunctl — create and manage persistent TUN/TAP interfaces 🌸

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🦋 SYNOPSIS 🦋

tunctl [ OPTIONS ] [ -u owner ] [ -t device-name ]

tunctl -d device-name

like, that's the whole vibe. either you're making an interface or you're deleting one, no in-between 💅

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🎀 DESCRIPTION 🎀

tunctl lets the host sysadmin preconfigure a TUN/TAP network interface so it's ready for a particular user before that user even shows up. iconic behaviour, honestly.

the deal is: that user gets to open and use the network/write side of the interface — the "wire" side, the fun side — but they can not change any aspects of the host side of the interface. that part stays locked down. main character energy on the user's side, zero admin powers, periodt. 🔥

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💖 OPTIONS 💖

• -b — brief output, bestie. prints just the interface name. no extra chatter, we love a minimalist.
• -n — create a point-to-point TUN interface without an Ethernet header. this gets automatically enabled if the desired interface name starts with "tun" — she knows what you meant 🧚
• -p — create a TAP type interface with an Ethernet header. automatically selected if the desired interface starts with "tap", or if you didn't give an interface name at all. slay, defaults 🎀
• -f tun-clone-device — specifies the tun clone device name. the default is /dev/net/tun, but some systems use /dev/misc/net/tun instead. not me checking your distro's vibe 🙈
• -d interfacename — delete the specified interfacename (i.e. set it to non-persistent). bye bestie 👋
• -u user — specifies the owner of the interface. this user is allowed to attach to the "network/wire" side.
• -g group — specifies the group of the interface. this group is allowed to attach to the "network/wire" side of the interface.
• -t interface — specifies the desired interface name. name her, don't be shy 💜

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🌈 USAGE 🌈

⭐ making one

to create an interface for use by a particular user, invoke tunctl without the -d option:

# tunctl -u someuser

Set 'tap0' persistent and owned by 'someuser'

see how she told you exactly what she did? obsessed. 💖

⭐ then configure it

then, configure the interface as normal — like, business as usual, no special tunctl magic here:

# ifconfig tap0 192.168.0.254 up

# route add -host 192.168.0.253 dev tap0

# bash -c 'echo 1 > /proc/sys/net/ipv4/conf/tap0/proxy_arp'

# arp -Ds 192.168.0.253 eth0 pub

ngl that's a whole lot of commands but they're literally copy-pastable, so we're fine 🫶

⭐ deleting it

to delete the interface, use the -d option:

# tunctl -d tap0

Set 'tap0' nonpersistent

and that's it. she's gone, she's non-persistent, she's at peace ✨

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🔍 SEE ALSO 🔍

the UserModeLinux-HOWTO — <URL:http://user-mode-linux.sourceforge.net/old/UserModeLinux-HOWTO.html> — go read it, iykyk 🦋

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👑 AUTHOR 👑

tunctl was originally written by Jeff Dike <jdike@karaya.com> as part of the User Mode Linux tools. the current version is maintained as a separate package by Henrik Nordstrom <henrik@henriknordstrom.net>. absolute legends, both of them 💅

this manual page was originally written by Matt Zimmerman <mdz@debian.org> for the Debian GNU/Linux system, based on examples from Jeff Dike. extended by Henrik Nordstrom <henrik@henriknordstrom.net> to cover all options supported. the way they kept it complete… we stan a thorough queen 🎀

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⭐ and that's the whole page! this version is dated 26 February 2024 and it's from the TUNCTL(8) manual (section 8, sysadmin club 👑). bye bestie, go make some interfaces 💖✨🦋