#153 Support Happy Eyeballs for BBS connections

[Chris Jacobs]

I added The Alien Mindbenders BBS and it works only when I use the IPv4 option.
The DNS gives both IPv4 and IPv6.

[Stephen James Hurd]

While DNS does give an IPv6 address, there doesn't seem to be a telnet server on it.

[Chris Jacobs]

Yes but if IPv6 is broken, no matter where, and IPv4 is also advertized I would like a fallback.

[Stephen James Hurd]

Are you suggesting that after the sixty second timeout it try the next address? I doubt that would be useful to anyone.

[Chris Jacobs]

I am certainly not suggesting sixty seconds.
How about 0.25 seconds like in Happy Eyeballs?
https://btw.media/en/quarter-second-bargain-behind-happy-eyeballs

[Stephen James Hurd]

The problem with using Happy Eyeballs is that many/most BBS connections aren't idempotent... as soon as a TCP connection is established, a resource is locked or consumed. Further, many BBS systems will strictly limit connections from the same IP address as well. Finally, some retro BBS systems used embedded stacks to convert to a serial connection and those can take as long as a couple seconds to SYN+ACK, and they also only allow a single incoming connection at a time.

In short, opening multiple simultaneous connections, then terminating all except the best one is a bad default strategy for BBSs.

[Stephen James Hurd]

Ticket moved from /p/syncterm/tickets/295/

Can't be converted:

• _output_type: Win32-GDI
• _found_in_version: 1.8

[Stephen James Hurd]

I've added an option for Happy Eyeballs to the v2.0a branch.