We use following IPs in our cron job executing bots:
220.127.116.11 (IPv6: 2607:5300:60:24de::)
18.104.22.168 (IPv6: 2607:5300:60:22cd::)
22.214.171.124 (IPv6: 2607:5300:60:22bd::)
126.96.36.199 (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