curl/docs/cmdline-opts/happy-eyeballs-timeout-ms.d
Daniel Stenberg 68784d73c3
curl.1: provide examples for each option
The file format for each option now features a "Example:" header that
can provide one or more examples that get rendered appropriately in the
output. All options MUST have at least one example or gen.pl complains
at build-time.

This fix also does a few other minor format and consistency cleanups.

Closes #7654
2021-09-01 14:02:43 +02:00

20 lines
893 B
D

Long: happy-eyeballs-timeout-ms
Arg: <milliseconds>
Help: Time for IPv6 before trying IPv4
Added: 7.59.0
Category: connection
Example: --happy-eyeballs-timeout-ms 500 $URL
---
Happy Eyeballs is an algorithm that attempts to connect to both IPv4 and IPv6
addresses for dual-stack hosts, giving IPv6 a head-start of the specified
number of milliseconds. If the IPv6 address cannot be connected to within that
time, then a connection attempt is made to the IPv4 address in parallel. The
first connection to be established is the one that is used.
The range of suggested useful values is limited. Happy Eyeballs RFC 6555 says
"It is RECOMMENDED that connection attempts be paced 150-250 ms apart to
balance human factors against network load." libcurl currently defaults to
200 ms. Firefox and Chrome currently default to 300 ms.
If this option is used several times, the last one will be used.