As per some older questions posted on SO about this, I have recently noticed a significant number (hundreds per day) of 408s in my Apache 2.4 logs, all of the following format:
X.X.X.X - - [12/Feb/2024:09:14:17 +0000] "-" 408 -
Ruling out the possibility that my server isn't able to process user-initiated requests due to lack of resources (because I know that my server has quite low utilisation) my understanding is that this is due to pre-connect in modern browsers, particularly Chrome.
I have read articles about this issue written around the time that the problem was first identified (which I think is 2013-2014) but I would like to know what the current state-of-the-art is. Specifically, is this now the expected behavior and these 408s are nothing to be concerned about? In Chrome, does the end user ever see these 408s resulting from pre-connect requests? Did HTTP/2 change things, and is this an ongoing issue for HTTP/1.1 servers that won't be resolved?
Thank you in advance for any suggestions/comments.