Dear All, The following message may be of interest to you if you're using Nagios (or variations like icinga) to query RIPE Atlas for status-checks. Yesterday morning our operations team made a change to the service configuration such that atlas.ripe.net only answers queries if they have proper Host: headers set. This is arguably a good operational practice, so we'd like to enforce it. However, one of the users running said nagios checks noticed that this causes 403 answers instead of the expected behaviour. We concluded that this is because the check_http plugin doesn't always set the Host: header. According to our statistics in total 12 users are affected, and since we could not foresee this problem, we temporarily reverted our configuration to the old settings. The fix on the client side is easy: one needs to add "-H atlas.ripe.net" parameter (or a similar change depending on forks and versions) to the checks. We'd like to ask our user to apply this change in the next two weeks in order to send well-formatted requests to our service. Thank you, Robert Kisteleki RIPE NCC