What You Need to Know About Uptime Monitoring Services
Uptime Monitoring Services are always third-party services that are used to verify and check how long a server is up and measure the time it is unreachable, to give an overview of the “uptime” of a server. They will alert users about downtimes and failures of detection, so that the right course of action can be taken to fix the issues. This is normally used to monitor the web hosting company to verify that the service that is being paid for is being delivered. There are many methods of delivery of the status reports, ranging from SMS, Instant Messages, and EMails.
There are different ports to watch and monitor to verify that a server is completely and fully working. The first and most obvious port is the HTTP request port, which is a port that is almost always open, but may be clogged with traffic and data, and is the port where all the HTTP responses from a server go through. This is one of the most important ports, because if it is down, then no HTTP requests will work and attempts to access websites will not go through.
If an uptime monitoring service detects this is down, it is imperative that it is fixed immediately. For servers that use email for sending and receiving, the SMTP port has to be watched. If it is down, then the server will be unable to receive messages and the sender will receive an email with an error message essentially stating that the message was unable to be sent, and to try again soon.
Another situationally important port is the POP3 port that allows client logins and access to email from an external client (like a cellphone, Mozilla Thunderbird, or others), or different webmail client. If the POP3 port is down, but SMTP is up, then the server can still send and receive email, it just will not be routed to other locations, and typically, the external client will give an error message.
IMAP is similar to POP3 in that it allows external client connections, but it is more advanced and has a wider feature set. It is slowly replacing POP3 as the external port of choice for sending and receiving email on external clients.
An FTP port is very important to have so that uploads and downloads will work on a website. This port is used whenever new files are added to the website, or when users use the protocol to download files from the server. DNS server tests will verify if the domain name lookup requests are going through effectively and routing the correct IP Address to the correct domain name. General TCP connections are typically also monitored, but there are many ports for that to monitor.
It is not widely agreed what a failure of a port consists of, so each monitoring service may be a little different. It is important to verify what the service means, and that the monitoring service uses multiple geographic locations to verify failure to make sure it is not isolated in one area.