On a domain, in the DNS settings is an SRV record named:
_autodiscover._tcp
and value is:
0 10 443 autodiscover.*hostname*.net.
What is it and what does it do?
I am migrating websites to a new server and I need to know how this will work with the new server on a different host.
SRV DNS records allow the use of DNS for publishing services and service discovery. Their main use is to allow services to run easily on non-standard ports and to reduce the configuration burden when setting up clients.
A SRV record has the following form:
_Service._Protocol.Name. TTL Class SRV Priority Weight Port Target
Service: the symbolic name of the service.
Protocol: the transport protocol of the service; this is usually either TCP or UDP.
Name: the domain name terminated with a . for which this record is valid - often omitted in DNS shorthand which then defaults to the zone name.
TTL: standard DNS time to live field.
Class: standard DNS class field (this is always IN for Internet).
Priority: the priority of the target host, lower value means more preferred.
Weight: A relative weight for records with the same priority.
Port: the TCP or UDP port on which the service is to be found.
Yours appears an example of an autodiscovery service :) pointing to TCP port 443 on the aptly named host autodiscover.*hostname*.net.
One such autodiscovery service seems to be used in automatically configuring MS Outlook but that may not be the only use-case.
It is likely related to your Exchange server.
These services enable things like email clients, FTP clients, etc to validate the mail or (S)FTP server name so as to enjoy greater security.
If such checking were not automatically done for email download, it might happen that a malicious email purporting to use your business email address as a sender (but actually emanating from a hacker employed by a rival business) could send an email to your bank with a separate Reply-To address (controlled by the hacker) and, if the recipient accepts the email as genuine, thus obtain sensitive information about your business.
Have a read here.
