Run on Port 80

0. Find the linked Node binary:

   which node
   

1. Find the real Node binary:

readlink -f /run/user/1000/fnm_multishells/2076_1764275467596/bin/node

You should get something like:

/home/youruser/.fnm/node-versions/v22.0.0/installation/bin/node

2. Give that binary permission to bind to low ports:

sudo setcap 'cap_net_bind_service=+ep' /home/youruser/.fnm/node-versions/vXX.XX.X/installation/bin/node

(replace the path with what you got from readlink -f)

3. Verify:

getcap /home/youruser/.fnm/node-versions/vXX.XX.X/installation/bin/node
# should output: cap_net_bind_service=ep

4. Now run Next.js as normal user:

PORT=80 npm run dev
# or

npx next dev -p 80

Notes:

• If you install a new Node version via fnm, repeat the setcap for that version’s node binary.
• You must run setcap on the actual binary, not the /run/user/... symlink.