Uptime Robot uses a distributed monitoring system to minimize false-positives.
All primary checks are made from the main engines in Dallas-USA. However, once a downtime is detected, secondary requests to verify this downtime is sent from remote nodes that are located in different countries/continents.
Whitelisting
If the monitoring works well for you, there is no need to take any actions. But, if you get any false/positives, there is a strong chance that the IPs used are blocked by your hosting provider.
Please make sure that you whitelist these IPs so that any requests that Uptime Robot send are not blocked.
Locations and IPs
The main monitoring location is in Dallas-USA and there are other nodes in other countries/continents to verify down statuses.
Here are all the locations and IPs used:
- 216.144.250.150 - (mail2.uptimerobot.com) (Dallas - USA)
- 69.162.124.226 - 2607:ff68:107::3 (engine5.uptimerobot.com) (Dallas - USA)
- 69.162.124.227 - 2607:ff68:107::4 (engine6.uptimerobot.com) (Dallas - USA)
- 69.162.124.228 - 2607:ff68:107::5 (engine7.uptimerobot.com) (Dallas - USA)
- 69.162.124.229 - 2607:ff68:107::6 (engine8.uptimerobot.com) (Dallas - USA)
- 69.162.124.230 - 2607:ff68:107::7 (engine9.uptimerobot.com) (Dallas - USA)
- 69.162.124.231 - 2607:ff68:107::8 (engine10.uptimerobot.com) (Dallas - USA)
- 69.162.124.232 - 2607:ff68:107::9 (engine11.uptimerobot.com) (Dallas - USA)
- 69.162.124.233 - 2607:ff68:107::10 (engine12.uptimerobot.com) (Dallas - USA)
- 69.162.124.234 - 2607:ff68:107::11 (engine13.uptimerobot.com) (Dallas - USA)
- 69.162.124.235 - 2607:ff68:107::12 (engine14.uptimerobot.com) (Dallas - USA)
- 69.162.124.236 -2607:ff68:107::13 (engine15.uptimerobot.com) (Dallas - USA)
- 69.162.124.237 - 2607:ff68:107::14 (engine16.uptimerobot.com) (Dallas - USA)
- 63.143.42.242 - 2607:ff68:107::15 (engine17.uptimerobot.com) (Dallas - USA)
- 63.143.42.243 - 2607:ff68:107::16 (engine18.uptimerobot.com) (Dallas - USA)
- 63.143.42.244 - 2607:ff68:107::17 (engine19.uptimerobot.com) (Dallas - USA)
- 63.143.42.245 - 2607:ff68:107::18 (engine20.uptimerobot.com) (Dallas - USA)
- 63.143.42.246 - 2607:ff68:107::19 (engine21.uptimerobot.com) (Dallas - USA)
- 63.143.42.247 - 2607:ff68:107::20 (engine22.uptimerobot.com) (Dallas - USA)
- 63.143.42.248 - 2607:ff68:107::21 (engine23.uptimerobot.com) (Dallas - USA)
- 63.143.42.249 - 2607:ff68:107::22 (engine24.uptimerobot.com) (Dallas - USA)
- 63.143.42.250 - 2607:ff68:107::23 (engine25.uptimerobot.com) (Dallas - USA)
- 63.143.42.251 - 2607:ff68:107::24 (engine26.uptimerobot.com) (Dallas - USA)
- 63.143.42.252 - 2607:ff68:107::25 (engine27.uptimerobot.com) (Dallas - USA)
- 63.143.42.253 - 2607:ff68:107::26 (engine28.uptimerobot.com) (Dallas - USA)
- 46.137.190.132 (remote1.uptimerobot.com) (Dublin - Ireland)
- 122.248.234.23 (remote2.uptimerobot.com) (Singapore)
- 188.226.183.141 - 2a03:b0c0:0:1010::832:1 (remote3.uptimerobot.com) (Amsterdam - Netherlands)
- 178.62.52.237 - 2a03:b0c0:1:d0::e54:a001 (remote4.uptimerobot.com) (London - UK)
- 54.79.28.129 (remote5.uptimerobot.com) (Sydney - Australia)
- 54.94.142.218 (remote6.uptimerobot.com) (São Paulo - Brazil)
- 104.131.107.63 - 2604:a880:800:10::4e6:f001 (remote7.uptimerobot.com) (New York - USA)
- 54.67.10.127 (remote8.uptimerobot.com) (California - USA)
- 54.64.67.106 (remote9.uptimerobot.com) (Tokyo - Japan)
- 159.203.30.41 - 2604:a880:cad:d0::122:7001 (remote10.uptimerobot.com) (Toronto - Canada)
- 46.101.250.135 - 2a03:b0c0:3:d0::33e:4001 (remote11.uptimerobot.com) (Frankfurt - Germany)
- 18.221.56.27 - 2600:1f16:775:3a01:70d6:601a:1eb5:dbb9 (remote12.uptimerobot.com) (Ohio - USA)
- 52.60.129.180 - 2600:1f11:56a:9000:23:651b:dac0:9be4 (remote13.uptimerobot.com) (Montreal - Canada)
- 159.89.8.111 - 2a03:b0c0:3:d0::44:f001 (remote14.uptimerobot.com) (Frankfurt-2 - Germany)
- 146.185.143.14 - 2a03:b0c0:0:1010::2b:b001 (remote15.uptimerobot.com) (Amsterdam-2 - Netherlands)
- 139.59.173.249 - 2a03:b0c0:1:d0::22:5001 (remote16.uptimerobot.com) (London-2 - UK)
- 165.227.83.148 - 2604:a880:400:d0::4f:3001 (remote17.uptimerobot.com) (New York-2 - USA)
- 128.199.195.156 - 2400:6180:0:d0::16:d001 (remote18.uptimerobot.com) (Singapore-2)
- 138.197.150.151 - 2604:a880:cad:d0::18:f001 (remote19.uptimerobot.com) (Toronto-2 - Canada)
- 34.233.66.117 - 2600:1f18:179:f900:88b2:b3d:e487:e2f4 (remote20.uptimerobot.com) (Virginia - USA)
And, here they are in .txt format in case you prefer to whitelist them in the firewall rules automatically:
P.S. Remote nodes currently have dynamic IPv6 addresses and they are not mentioned for this reason.