Last week a VPS crashed multiple times and I try to figure out, why.
There is a pretty high amount of 404 in apache's log for /autodiscover/autodiscover.xml The logs aren't in chronological order …
aa.bb.cc.dd - - [02/Feb/2018:09:50:11 +0100] "POST /autodiscover/autodiscover.xml HTTP/1.1" 301 258 "-" "Microsoft Office/14.0 (Windows NT 6.1; Microsoft Outlook 14.0.7192; Pro)"
aa.bb.cc.dd - - [02/Feb/2018:09:55:32 +0100] "POST /autodiscover/autodiscover.xml HTTP/1.1" 301 258 "-" "Microsoft Office/14.0 (Windows NT 6.1; Microsoft Outlook 14.0.7192; Pro)"
aa.bb.cc.dd - - [02/Feb/2018:09:58:56 +0100] "POST /autodiscover/autodiscover.xml HTTP/1.1" 301 258 "-" "Microsoft Office/14.0 (Windows NT 6.1; Microsoft Outlook 14.0.7192; Pro)"
aa.bb.cc.dd - - [02/Feb/2018:10:04:02 +0100] "POST /autodiscover/autodiscover.xml HTTP/1.1" 301 258 "-" "Microsoft Office/14.0 (Windows NT 6.1; Microsoft Outlook 14.0.7192; Pro)"
aa.bb.cc.dd - - [02/Feb/2018:09:53:50 +0100] "POST /autodiscover/autodiscover.xml HTTP/1.1" 301 258 "-" "Microsoft Office/14.0 (Windows NT 6.1; Microsoft Outlook 14.0.7192; Pro)"
aa.bb.cc.dd - - [02/Feb/2018:10:00:53 +0100] "POST /autodiscover/autodiscover.xml HTTP/1.1" 301 258 "-" "Microsoft Office/14.0 (Windows NT 6.1; Microsoft Outlook 14.0.7192; Pro)"
aa.bb.cc.dd - - [02/Feb/2018:10:00:53 +0100] "POST /autodiscover/autodiscover.xml HTTP/1.1" 301 258 "-" "Microsoft Office/14.0 (Windows NT 6.1; Microsoft Outlook 14.0.7192; Pro)"
aa.bb.cc.dd - - [02/Feb/2018:10:09:06 +0100] "POST /autodiscover/autodiscover.xml HTTP/1.1" 301 258 "-" "Microsoft Office/14.0 (Windows NT 6.1; Microsoft Outlook 14.0.7192; Pro)"
aa.bb.cc.dd - - [02/Feb/2018:09:50:11 +0100] "POST /autodiscover/autodiscover.xml HTTP/1.1" 301 258 "-" "Microsoft Office/14.0 (Windows NT 6.1; Microsoft Outlook 14.0.7192; Pro)"
aa.bb.cc.dd - - [02/Feb/2018:10:11:33 +0100] "POST /autodiscover/autodiscover.xml HTTP/1.1" 301 258 "-" "Microsoft Office/14.0 (Windows NT 6.1; Microsoft Outlook 14.0.7192; Pro)"
aa.bb.cc.dd - - [02/Feb/2018:10:06:12 +0100] "POST /autodiscover/autodiscover.xml HTTP/1.1" 301 258 "-" "Microsoft Office/14.0 (Windows NT 6.1; Microsoft Outlook 14.0.7192; Pro)"
I've read logs are created in order of request, not completion. Does it mean the log from 09:53:50 needed at least about 7 minutes to complete?
What is Exchange posting to that URL? Why does it take several minutes? Do you think that can crash a server?
FYI The VPS (2GB RAM, FreeBSD, Apache) has a really small website/CMS installed (which generates the 404 page as well). My client uses (somewhere else) an Exchange-Server associated with the domain.