Show HN: Port Zero – How I learned to stop worrying and love PORT=0 • Hacker News Board

Re: Show HN: Port Zero – How I learned to stop worrying and love PORT=0

#21

Post by protocolture » Fri, Jul 31, 2026, 12:04 AM UTC

>Recently I wasted several hours wrangling my dev environment only to find out that the browser frontend was talking to the wrong version of the backend.

For 50 dollars a month you can rent my WebNote application, where you can write down the ports you are using for each of your development applications. With this amazing technology you can compare your environment issues against your documented port choices eliminating port conflicts forever.

Re: Show HN: Port Zero – How I learned to stop worrying and love PORT=0

#22

Post by c-hendricks » Fri, Jul 31, 2026, 12:27 AM UTC

mjmas wrote: post #16

Why not have your program just listen on port 80 on an address under 127.0.0.0/8? You will need to run sysctl net.ipv4.ip_unprivileged_port_start=80 before you start, but after that you have 2 ** 24 addresses to choose from. And the browser will be happy to treat it as a secure page as well as do proper cookie isolation.

Is that the only thing governing unprivileged ports, or do programs also implement their own rules?

Re: Show HN: Port Zero – How I learned to stop worrying and love PORT=0

#23

Post by dhchun1203 » Fri, Jul 31, 2026, 12:51 AM UTC

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Re: Show HN: Port Zero – How I learned to stop worrying and love PORT=0

#24

Post by neilalexander » Fri, Jul 31, 2026, 8:38 AM UTC

mjmas wrote: post #16

Why not have your program just listen on port 80 on an address under 127.0.0.0/8? You will need to run sysctl net.ipv4.ip_unprivileged_port_start=80 before you start, but after that you have 2 ** 24 addresses to choose from. And the browser will be happy to treat it as a secure page as well as do proper cookie isolation.

The CAP_NET_BIND_SERVICE capability on Linux is far less of a blunt instrument that applies to a single process rather than system-wide.