We use following IPs in our cron job executing bots:
192.99.12.158 (IPv6: 2607:5300:60:3d9e::1)
198.245.51.209 (IPv6: 2607:5300:60:6d1::1)
198.245.62.5 (IPv6: 2607:5300:60:205::1)
198.100.146.163 (IPv6: 2607:5300:60:9a3::1)

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.