Symptoms
Are you seeing your server appear to be running slower or showing a high amount of CPU usage along with a large number of connections to proxy-subdomains-vhost.localhost?
Description
The proxy-subdomain-vhost.localhost is what is used for the following ServerAliases for each domain defined on your server when it is setup on cPanel.
For more information about Service Subdomains and how it is setup, please refer to the documentation below.
https://docs.cpanel.net/knowledge-base/general-systems-administration/service-and-proxy-subdomains/
To quickly check for which service subdomains are the most used. You may search the
/etc/apache2/logs/domlogs/proxy-subdomains-vhost.localhost
for more details.
Below is a command that may help isolate which domains are being used the most via the webmail service subdomains as an example.
For the webmail service subdomain, this command will show the number of "accesses" for each domain, from the most to the least.
grep 'http://webmail.' /etc/apache2/logs/domlogs/proxy-subdomains-vhost.localhost |awk '{print $11}' | awk -F '/' '{print $3}' | sort | uniq -c | sort -k 1 -n | tac | less
To check the other subdomains, replace
http://webmail.
With any of the following entries to check each service subdomain access details.
cpanel - cPanel Service Subdomain - https://docs.cpanel.net/cpanel/
whm - WHM Service Subdomain - https://docs.cpanel.net/whm/
webdisk - The Webdisk Service Subdomain - https://docs.cpanel.net/knowledge-base/third-party/connect-to-web-disk-with-third-party-software/
autoconfig - Along with Autodiscover, used for automatic email client configuration - https://docs.cpanel.net/knowledge-base/email/autoconfig-and-autodiscover/
autodiscover - See Autoconfig
cpcalendars - Along with cpcalendars, this is used for the setup of calendars and contacts (CalDav and CardDav) for mail clients - https://docs.cpanel.net/knowledge-base/webmail/how-to-set-up-calendars-and-contacts/
cpcontacts - See cpcalendars