We use following IPs in our cron job executing bots:
22.214.171.124 (IPv6: 2607:5300:60:24de::)
126.96.36.199 (IPv6: 2607:5300:60:22cd::)
188.8.131.52 (IPv6: 2607:5300:60:22bd::)
184.108.40.206 (IPv6: 2607:5300:60:4b6e::)
Please make sure our IPs can reach your cron job scripts/programs.
Our bots will use IPv4 unless the destination server forces us to use IPv6.
A JSON format IP list could be found at https://www.easycron.com/ips.json