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[2007-02-10 19:51 UTC] tony2001@php.net
[2011-10-11 06:26 UTC] georg dot hoellrigl at xidras dot com
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Last updated: Thu Oct 30 18:00:02 2025 UTC |
Description: ------------ fsockopen() always asks your DNS server for the IP address of a connection before it opens it, instead of trying to look in the local cache first. I believe this is unexpected and performance-wise is a very undesirable operation. See reproduce code... Reproduce code: --------------- <?php for ($i = 0; $i < 50; $i++) { $errno = $errstr = ""; //$ip = gethostbyname("php.net"); $a = fsockopen($ip,22,$errno,$errstr,10); //FAST way $a = fsockopen("php.net",22,$errno,$errstr,10); //SLOW way $ab = fread($a,4096); unset($a, $ab); } ?> Expected result: ---------------- While running the slower code above exactly as is, you can packet sniff and view 50 full requests for the domain php.net. This is unoptimized and causes this code to run extremely slow. When running with the fast way (change lines commented out) the above code runs a few hundred percent faster. Upon a packet sniff you can watch 1 or two requests for php.net being sent to your DNS server which I believe is the desired result. NOTE: In the code above I do have the workaround by connecting with the IP instead by using gethostbyname() first which appears to use the local DNS cache. Actual result: -------------- The code above should run exactly the same speed either way. fsockopen should be using the local machine's DNS cache and not have to query the DNS server upon every request when given a DNS name to connect to.