BYOIP for Disaster Recovery: Keeping Addresses Stable During Failover

Disaster recovery can fail at the network edge even when backup compute is ready. If the recovery site uses different public addresses, teams may need emergency changes to DNS, allowlists, firewall rules, and partner integrations.

BYOIP for disaster recovery is a design in which a company uses its own IPv4 range across primary and recovery infrastructure. Its purpose is to preserve public address continuity during failover so that services can move between sites without forcing emergency re-IP work across external dependencies.

Why does address continuity matter during disaster recovery?

A recovery plan usually focuses on restoring applications and data, but public IPs can be just as important. Customers, partners, payment systems, VPN peers, and APIs may trust specific source or destination addresses.

Keeping the same range reduces the number of changes that must happen during an incident. External allowlists can remain valid, firewall rules do not need mass updates, and integrations can continue to recognize the same network identity while traffic moves to the recovery environment.

How should the failover routing model be defined before an incident?

The recovery design should state which site announces the prefix during normal operation and what changes during failover. This avoids ambiguous routing or unintended announcements from two locations.

The routing plan should define:

primary and recovery origin ASN;
ROA coverage for the intended announcements;
IRR records and upstream filtering;
route withdrawal conditions at the primary site;
activation conditions at the recovery site;
monitoring of global BGP visibility.

The sequence matters because partial propagation can send different networks to different sites.

What must be prepared at the recovery site before the same IPv4 block can be used?

The recovery environment needs more than spare servers. It must accept the same public range under the required routing and security model.

The technical preparation should include:

provider support for the required prefix size;
rights to use and announce the IPv4 block;
BGP sessions and upstream connectivity;
firewall, DDoS, NAT, and load-balancer configuration;
required LOA or provider authorization;
monitoring for reachability after the route changes.

If the recovery platform cannot announce the range under the planned conditions, BYOIP will not provide address continuity during the incident.

How does BYOIP change the role of DNS during failover?

When the public IP remains the same, DNS does not need to replace the service address. This removes one source of delay because failover does not depend on every resolver seeing a new A record.

DNS still needs review. PTR records, region-specific names, load-balancer targets, and service records can depend on the underlying architecture even when the public IPv4 address remains unchanged. Address stability therefore reduces DNS changes but does not make the DNS layer irrelevant.

How should a disaster recovery team test the route handoff?

A DR test should verify that the address range moves from the primary path to the recovery path under production-like conditions. Checking BGP configuration alone is not enough.

A useful test should measure:

time required to withdraw the primary route;
time until the recovery path becomes visible;
reachability from several networks and regions;
RPKI state during the transition;
operation of APIs, VPNs, and partner connections;
restoration of traffic when the primary site returns.

The result should be compared with recovery objectives so routing convergence is included in DR timing.

Why can BYOIP still fail during a real disaster?

Address continuity does not guarantee service continuity. The recovery route may be filtered, a ROA may not authorize the recovery ASN, or security infrastructure at the backup site may not be ready for production traffic.

Applications can also fail if they depend on regional services that do not exist at the recovery location. BYOIP removes one category of change, not the need for a complete DR design.

How should traffic return to the primary site after recovery?

Failback should be planned as carefully as failover. Once the primary environment is stable, the team needs a controlled sequence for restoring the preferred route, confirming reachability, and withdrawing the temporary recovery path.

The return plan should verify application health, external integrations, and route visibility after traffic moves back. Without it, recovery can still end with inconsistent routing or unnecessary dual announcements.

When can leased IPv4 be used for disaster recovery?

A company can rent IPv4 addresses for DR if the agreement allows use at both the primary and recovery environments and authorizes the required origin ASN or routing model. The lease term should cover testing, standby use, and failback after an incident.

For infrastructure that requires long-term control over the same public range, a company may instead buy IPv4 addresses when ownership better matches the expected recovery architecture.

Which disaster recovery questions deserve separate attention?

Can one IPv4 block be announced from two sites at the same time?

Yes, if the routing design intentionally supports it. The policy must still define which path should receive traffic and prevent unintended conflicts.

Does DNS always stay unchanged during failover?

No. The main A record may remain stable, but other records and service dependencies can still change with the recovery architecture.

Can a leased IPv4 block be used for DR testing?

Yes, if the lease permits the required routing model and use from the recovery environment.

How often should BYOIP failover be tested?

After major routing, provider, security, or platform changes and according to the organization’s regular DR schedule.

Where can a company source portable IPv4 capacity for disaster recovery?

When a disaster recovery design requires stable public addresses across primary and backup sites, InterLIR provides infrastructure for leasing or purchasing IPv4 blocks. The resource can be prepared and tested before an incident so failover does not depend on emergency address replacement.