________________________________ From: Daniel Stenberg <dan...@haxx.se> Sent: Wednesday, April 10, 2019 4:03 AM To: Weixi Li via curl-library Cc: Weixi Li Subject: Re: Reduce CURLOPT_CONNECTTIMEOUT
>The default 300 seconds was just arbitratrily picked at some point in time to >be very conservative but still at least give up at some point. > >It is certinly safe to reduce the timeout to whatever value you think is fine. >You know your conditions and how long you're willing to wait for curl to try. >Having it set too low will only risk you canceling a connecton that could have >connected fine if you gave it more time. > >Most systems will resend lost TCP SYN packets a few times with an exponential >backoff and in 30 seconds not all have finished retrying. But the connect >phase in curl also includes name resolving and TLS handshake etc so a slow >network with packet loss could at least in theory take a long time to connect. >In reality I doubt you see very many connects taking more than just a few >seconds . Thank you very much for the comments. We did notice an interesting case: for an SFTP connection via IP, the Squid proxy would do a reverse DNS lookup which would require 30 seconds to fail eventually. So it's probably unsafe to set the connection timeout too low.
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