At-Home VPN

Recap: I can ssh to port 2048 on davidyim.name - but it does not connect to home Mac Mini.

Currently running autossh -M 0 -o ServerAliveInterval=30 -o ServerAliveCountMax=3 -nNTv -R 0.0.0.0:2048:localhost:22 root@davidyim.name from Mac Mini

Modifications made to /etc/ssh/sshd_config

• Enabled GatewayPorts yes
• Enabled AllowTcpForwarding yes

Current command: ssh -R 2048:localhost:22 root@davidyim.name -N -f -o ExitOnForwardFailure=yes (following https://www.tencentcloud.com/techpedia/144010)

Listening to processes at port 2048: lsof -i :2048

I briefly made a connection, but cannot replicate the situation

I can consistently make the connection now:

• SSH daemon listening to Port 2048 was not necessary - this conflicts with reverse tunnelling
• As long as reverse tunneling process has started + that specific port is open on ufw = sufficient
• The above command actually backgrounds the process
• The user name connecting should be local machine user name: ssh -p 2049 davidyim2@davidyim.name

Created a file ~/autossh_reversetunnel.sh and added to Mac OS Login Items:

• autossh -M 0 -o "ServerAliveInterval 30" -o "ServerAliveCountMax 3" -o "ExitOnForwardFailure yes" -N -f -R 2049:localhost:22 root@davidyim.name

One final word: the guide includes practical use cases, one of them being VNC - will investigate, but for now, this project is complete.

Retrying...

1. ufw allow 2048/tcp
   • The output = Skipping adding existing rule

   • Skipping adding existing rule (v6)

2. Edited /etc/ssh/sshd_config

   • Uncommented Port 22

   • Added Port 2048

3. systemctl restart ssh

No effect after this:

• davidyim@ctsadmins-MacBook-Pro ~ % ssh -p 2048 root@davidyim.name
ssh: connect to host davidyim.name port 2048: Connection refused

• davidyim2@df01898ef77af unzip % nc -zv davidyim.name 2048
nc: connectx to davidyim.name port 2048 (tcp) failed: Connection refused

Google suggested:

• systemctl disable --now ssh.socket
systemctl enable --now ssh.service

(Still does not work)

Google diagnosed the problem correctly: there was a remnant process listening to port 2048 - killing that process and restarted sshd = I can connect to 2048 now. But connecting to port 2048 does not connect me to local Mac Mini

I started following this guide but ended up with ssh refusing service at all ports - fixed, is now documenting everything:

So far:

• Installed autossh on home Mac Mini, running an instance
• No startup script yet - need to figure out how to do that on Mac OS (old - Catalina version)
• Allowed connection to the port of my choosing using ufw, can see using ufw status

Researching:

• Set up VPN at home
• How to anchor dynamic IP address to vpn.davidyim.name subdomain
  • Hmm I thought I could get assigned a static IP address with TekSavvy (with cost)