Bug #80830 [Com]: Running out of local ports when using curl

Edit report at https://bugs.php.net/bug.php?id=80830&edit=1 ID: 80830 Comment by: michael dot mckeever at bosch dot com Reported by: external dot maik dot dieterich at bosch dot com Summary: Running out of local ports when using curl Status: Not a bug Type: Bug Package: Network related Operating System: Windows Server 2019 PHP Version: 7.4.15 Assigned To: cmb Block user comment: N Private report: N New Comment: Thank you @danack and @cmb for the quick response. Your suggestions with reusing the the curl handle is correct if you're using a cli application and you're in control of the environment. The problem described by Maik is that if you're using apache you can't reuse curl handles. @rtrtrtrtrt, your comment is unfortunately not helping in this topic ;-) The key question is, why is the mass usage of curl.exe not causing TIME_WAITs and the php libcurl functions causing TIME_WAITs. Furthermore the php functinos are not causing TIME_WAITs to the called server as one would expect, but it's causing TIME_WAITs for some kind of local redirects. It's causing localhost to localhost TIME_WAITs. Previous Comments: ------------------------------------------------------------------------ [2021-03-04 20:07:01] rtrtrtrtrt at dfdfdfdf dot dfd it's just how TCP works https://superuser.com/questions/173535/what-are-close-wait-and-time-wait-states ------------------------------------------------------------------------ [2021-03-04 18:32:27] external dot maik dot dieterich at bosch dot com First thanks for the quick response. What is not clear for me, is why the connection I open to the external server can be closed immediately and why this local local port connections, which i do not have if i use curl from command line, are still open even if the external connection I open is closed. Because each connection is opened in a different thread i think I can not reuse them. ------------------------------------------------------------------------ [2021-03-04 17:19:18] cmb@php.net I think @danack is spot on. But instead of fiddling with these Windows settings, I suggest to re-use the same curl resource (object as of PHP 8.0.0), like described by Dan, to avoid calling curl_easy_cleanup() under the hood, because[1] | re-using handles is a key to good performance with libcurl Anyway, this is not a PHP issue. [1] <https://curl.se/libcurl/c/curl_easy_cleanup.html> ------------------------------------------------------------------------ [2021-03-04 15:51:58] danack@php.net This is a feature of Windows. It keeps network connections open for a long time by default. You could either work around this by "Adjust the MaxUserPort and TcpTimedWaitDelay settings" - https://docs.microsoft.com/en-us/biztalk/technical-guides/settings-that-can-be-modified-to-improve-network-performance Or you can re-use the same Curl object, which will almost certainly re-use the underlying network connection if possible, ``` $ch = curl_init($url); for($i = 0; $i < 5000; $i++) { curl_setopt($ch, CURLOPT_URL, $url); $response = curl_exec($ch); } curl_close($ch); ``` I'll leave it open, so that someone who is more sure that there is nothing to be done in PHP, can close it. ------------------------------------------------------------------------ [2021-03-04 14:27:36] external dot maik dot dieterich at bosch dot com Description: ------------ We are having an application which runs in Apache and gets files via an API. These files are stored on a storage over a rest API. For transferring the files to the storage we are using PHP with curl. Php opens a local port to local port connection when a curl handle is initialized with a connection to an external server. This local connection stays in TIME_WAIT after the external connection and the curl handle is closed. When open connections with curl from command line without PHP these local port local port connections are not opened. Test script: --------------- for($i = 0; $i < 5000; $i++) { $ch = curl_init("your url"); $response = curl_exec($ch); curl_close($ch); } Expected result: ---------------- No connections in TIME_WAIT. Actual result: -------------- Many connections in TIME_WAIT. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=80830&edit=1