Connect. Secure. Manage.
Public IP Address Migration
Plan changes to public IP addressing across Cisco or Meraki environments, identifying published services, allowlists, VPN peers and transition risks.
Devices supported
across the UK
Client locations
supported
Traffic handled
at peak time
Average
response time
Average response is not a resolution time or a contractual guarantee. Support scope and response commitments are agreed for each engagement.
Public IP address migration changes how outside users and services reach your network, and sometimes how your outgoing traffic is seen. We plan Cisco and Meraki routes, address translation and third-party access rules with the DNS changes. The work starts with a full dependency list so important services are included in the move and tests.
The whole path
Understand how sites, providers, cloud networks and security controls fit together.
Resilience that can be tested
Separate a second circuit from genuine end-to-end service resilience.
Provider coordination
Keep addressing, routing and escalation ownership clear across organisations.
Establish which addresses are changing and why
The migration may follow a provider change, network redesign, acquisition or a move to another hosting setup. We find the current and proposed address allocations and confirm who is authorised to use or advertise them. An address supplied by one provider should not be assumed portable to another connection without checking the actual arrangement.
The inventory distinguishes addresses used for published services, outbound translation, VPN endpoints, management and specialist interconnects. These roles can have different migration methods. An address that appears unused in a short traffic sample may still support an occasional supplier or recovery workflow, so ownership matters as much as observation.
Standards & partnerships
Confidence in the team behind your network.
Cisco Partner
Cisco Meraki
Cyber Essentials
Cyber Essentials PlusMCI Network Services is operated by Proxar Ltd. Certifications apply to the certified legal entity and the scope of its certificates. View accreditation information
Build the external dependency register
We identify systems that rely on the old address directly or through a name. External allowlists, partner connections, monitoring services and app integrations may require changes by another organisation. The register records the owner, required update, lead time and test needed to confirm the dependency has moved.
Hard-coded addresses receive particular attention. DNS changes cannot help an app or device configured with a literal IP address. We work with the relevant owners to identify those uses and establish a supported replacement, avoiding an assumption that every consumer follows the same published hostname.
A useful starting point
Not sure where to start?
Bring the requirement. We will help you define the engineering work.
Review routing and advertisement requirements
Where the migration affects routed prefixes, the plan includes provider coordination, filtering and any route-origin records applicable to the allocation. We set out when old and new prefixes are announced or withdrawn and how traffic should behave during coexistence. An incorrect advertisement can affect networks beyond the customer's own estate.
For simpler provider-assigned arrangements, interface addressing and default routing still need verification. The new service must accept the intended source addresses and return traffic correctly. We compare the provider specification with the actual edge setup before moving production translations or published destinations.
Different environments. The same care.
Built around the work
your network supports.
Finance, banking and the wider private sector. We start with the systems and people that depend on your connections.
Finance & banking
Market-data paths, routing and provider coordination on clients’ behalf.
Financial-market services ↗Offices & multi-site teams
Reliable access between people, workplaces and business applications.
Office network design ↗Data centres & cloud
Network boundaries, workload connections and operational ownership.
Data centre networks ↗Coordinate NAT and security policy
Address translation, firewall objects and access rules often contain the old public addresses in several places. We identify those references and check the platform's actual review behaviour. Changing a NAT rule without considering the associated policy or return route can leave a service exposed incorrectly or unreachable.
Outbound source addresses matter and inbound destinations. A business app may accept connections only from a known public address, and a current session may not survive a move to another one. We test the relevant workflow and coordinate the external permission before treating outbound access as a routine part of cutover.
Plan DNS and service discovery realistically
Public records are updated through an agreed sequence, taking current caches into account. A shorter record lifetime can help a planned transition. But it does not immediately remove older cached answers. We check which services can tolerate a period of mixed resolution and whether both old and new endpoints can remain available during that time.
Certificates, app names and other discovery mechanisms are reviewed where affected. A public address change does not always require a certificate change. But a hostname or endpoint redesign may. The plan distinguishes those cases rather than applying an unnecessary blanket certificate replacement.
Validate from outside the network
Testing uses appropriate external sources to confirm that published services reach the intended destination and that restricted services remain inaccessible. We also check outbound traffic as seen by important counterparties. Testing only from an internal network can conceal translation or routing behaviour that differs for real external users.
The cutover has clear acceptance and rollback criteria. We check which changes can be reversed locally and which depend on another party or cached information. The observation period is chosen according to the service dependencies, not merely the time needed to complete setup commands.
Retire old addresses and references safely
After acceptance, the old translations, routes, records and external permissions are reviewed for removal. Unused public addresses and stale allowlist entries can create future confusion or exposure, particularly when an allocation returns to a provider. Retirement is therefore part of the migration rather than an optional housekeeping task.
MCI can manage the network scope of an address change alongside an internet provider migration or a separate infrastructure project. Share the address roles, known external dependencies and timing constraints. We can prepare a controlled plan that preserves the services you need without assuming DNS alone describes every relationship with the outside world.
Technical references
- ExpressRoute routing requirements — Microsoft
- AWS Direct Connect overview — Amazon Web Services
Talk to a specialist
What does your network need next?
Tell us what you are planning, changing or trying to improve. We will help define a practical next step and the engineering scope.
+44 203 196 6566Choose option 1
sales@proxar.co.ukUK-wide service.
Most of our engineers are based in Kent, with a focus on London, Sussex, Essex and Berkshire.
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