Monthly Archives: February 2019

All the requests sent from Uptime Robot are using pre-defined IPs to make sure that we all know the source of the requests.

A new IP block is being added to the system:

  • 216.245.221.80/28

And, if exists, please make sure it is whitelisted in your firewalls.

Also, the full list of the IPs used can be found here.

P.S.> If you had never needed to whitelist or take action regarding to  Uptime Robot’s IPs in the past, then you probably don’t need to take any action and can ignore this info.

Uptime Robot treats all HTTP statuses equally. They mean either up or down… except HTTP 401.

HTTP 401 is expected in some situations and not expected in others. Currently, HTTP 401 is handled as:

  • If auth info is mentioned in monitor’s settings but HTTP 401 is returned, monitor is marked as down
  • if no auth info is mentioned but HTTP 401 is returned, it is marked as up

which looked like the best way at the early days of Uptime Robot.

Yet, there are edge cases on both scenarios like “a monitor with no auth info returning HTTP 401″ may also mean that the site/server is experiencing configuration issues and this must be detected as down.

The change

As there is now a Pro Plan feature to customize HTTP statuses, Uptime Robot will start treating HTTP 401 just like other HTTP statuses (which are equal to or bigger than 400):

  • will be considered as down by default no matter auth info exists or not
  • if needed, it will be customizable with the HTTP status customization feature.

This change will give room to handling this HTTP status however preferred and the change is planned to go live on 1 March 2019.