HUB

Related pages

• Tinc
• XPUB HUB Node: Sandbox
• XPUB other HUB nodes

HUB nodes

If you still need to install Tinc follow the instructions in the page Tinc

WAT

HUB or https://hub.xpub.nl is a VPN wonder to gazillions XPUB things.

You will need to:

• 0. Determine IP address of a new thing (see below)
• 1. Add a new thing (see below)
• 2. Ask user to give you preferred username & a new ssh pubkey (see below)
• 3. Add a new jump user (see below)
• 3. Jump user connects to his machine (see below)

Adding a new thing

See XPUB_HUB_New_Nodes

Only gnd or a should do that. Also we will only add things that can only be ssh'ed via keys, no passwd logins plz.

• On xvm:

tinc -n hub invite ${NODE_NAME}

• On ${NODE_NAME}:

Generating a ssh pubkey for the jump user

This should be done by the users themselves. This only applies to linux-like OS's. Users should be made aware what ssh keys are.

This generates a new key with a default name, so if the user already has an existing key, they should name it differently, so the existing one is not overwritten. The key should be protected by a passphrase.

ssh-keygen -t ed25519 -b 320 

Once the key is generated, we will need the public key (pubkey). Usually it would be a file called id_ed25519.pub located in ~/.ssh. Just cat the file and send us the contents.
♥♥♥ Please be aware there is also a file called id_ed25519. This is the private key. Dont ever send or disclose the private key ! ♥♥♥

cat ~/.ssh/id_ed25519.pub

You can also send id_ed25519.pub as an attachment. If you named your key differently, it will be a file called $NAME.pub

Adding a jump user on XVM

There is a script called add_jumpuser. It adds a new user on XVM, that is only allowed to ssh into the remote machine. You will need:

• Username for the user
• IP of the machine (see below for allocation)
• ED25519 pubkey from the user

Once you have all of this, just run on XVM (note the single quotes around the ssh pubkey):

/root/scripts/add_jumpuser.sh USERNAME IP 'PUBKEY'

eg.:
/root/scripts/add_jumpuser.sh lol 10.0.0.666 'ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIE29EOVCl0/WjknAoEEEZSPUyCWQKNoXX2HCC123456 some1@host'

When removing the user on XVM:

• userdel -r USERNAME
• remove USERNAME from AllowUsers in sshd_config
• restart sshd

IP allocation

• 1-9: XPUB main servers
• 10-99: shared machines used by the whole course (for admin or lessons or multi-user projects/libraries/etc)
• 100-254: personal and/or grad projects machines

Subnet       Node             ???
------       ----             ---
10.0.0.1     xvm              XPUB server, tincd overlord, destroyer of pads
10.0.0.10    skattkista       Borg Central
10.0.0.11    sandbox          xpub1 sandbox (2019-2021) 
10.0.0.100   wizardcity       Aymeric
10.0.0.101   screaming        Angeliki (student 2017-2019)
10.0.0.102   warnet           Tash (student 2017-2019)  - offline
10.0.0.???   food             Alice -- misconfigured, lost in ether
10.0.0.103   bootleglib       Simon (student 2018-2020)
10.0.0.104   systers          Artemis (student 2018-2020)
10.0.0.105   watermark        Pedro (student 2018-2020)
10.0.0.106   ilinx            Tancredi (student 2018-2020)
10.0.0.107   repeater         Biyi (student 2018-2020)
10.0.0.108   netcare          Rita (student 2018-2020)
10.0.0.109   cartographies    Paloma (student 2018-2020)
10.0.0.110   loopdeloop       Steve (xpub staff)

How to SSH to HUB nodes

On the user's personal machine (where the public key was generated) just:

ssh -J xpub.nl:2501 $IP

If for any reason it doesnt work, please send us the output of:

ssh -J xpub.nl:2501 $IP -vvv

~/.ssh/config

Here is a ssh configuration which should allow you to ssh easily from your local machine to one of the Hub nodes

using only:

ssh hub.nodename

By adding to ~/.ssh/config the following configuration, and changing with the correct details:

Host hub.nodename 
User username
Hostname  10.0.0.XXX
ProxyJump username@xpub.nl:2501
Identityfile ~/.ssh/id_rsa
Serveraliveinterval 30

Where:

• nodename: is the name you would like to give this node of hub.
• XXX: termination if node's IP
• username: your username in the Pi and Xpub server (should be the same)
• ~/.ssh/id_rsa location of the private keys