Renumbering — changing all your public IP addresses — is one of IT’s most underestimated projects: DNS, certificates, partner whitelists, VPNs, licenses… Two strategies avoid it:
- Your own provider-independent (PI) addresses + your AS: you announce your prefixes wherever you want, with whichever carrier you want. The royal road once infrastructure matters.
- Addresses from a co-present carrier: without your own AS, pick a carrier present at both your sites — the same AS announces the pool on both sides, and your IPs follow during a failover or a move. Our co-presence search verifies exactly that, data center by data center.
If renumbering is unavoidable: DNS TTLs at 300 s a week ahead, an inventory of third parties that hard-coded your IPs, dual-running both ranges, and recreating PTRs (reverse DNS) at the new carrier — vital for outbound mail.