Look at the services your organisation uses, and work out whether and how you can access them when you migrate to PSN. After you request access to the network the PSN team will ask you to show us the network design for your connectivity so we can help you find the best way to connect to the services you need.
Review the PSN code of connection
You should start planning the work needed to make sure your network meets the standards allowing you to connect. Before your organisation can connect to PSN, or use it to receive PSN services, you must be PSN-compliant.
You’ll need to complete and submit a PSN Code of Connection (CoCo) and other supporting documents to PSN at least one month before expiry of your current CoCo to get your PSN compliance. If you are a supplier of services you will also need to fill out a Code of Practice (CoP).
Read the customer compliance guide or the service provider compliance guide for further information.
Request services
You can request services like IP addresses, DNS names and encryption services from PSN.
You may need a set of IP addresses for new connections and services . Complete the IP address allocation form. The PSN team will allocate these if your request is approved.
If your organisation is moving from GCF to PSN, complete the GCF to PSN IP allocation form.
If you have services like intranets and email that you want to make available to others on PSN you’ll need to create DNS entries for them. To do this:
You may want encryption on your network service. To do this:
- choose a supplier that offers an encrypted service - the supplier may need to do additional configuration testing which can take a significantly longer period of time
- make sure the supplier knows which services you need access to. Depending on the service more configuration may be required.
Read the Inter-Provider Encryption Domain (IPED) service document to learn more about using encryption on the PSN.
Buy network connectivity to PSN: choose your service provider
You’ll need to select a connectivity services provider to connect to PSN. These providers are Direct Network Service Providers (DNSPs). You can buy their services under the Crown Commercial Service (CCS) PSN Framework. If you’re going to change your DNSP then bear in mind that termination of your current connectivity typically has a lead time of 30 days.
Request changes from service providers
You must make sure you have access to the PSN services you need from your new connection. The PSN team will provide new IP addresses for new customers connecting to the network. Make sure that you know all the services that you’re currently accessing and contact the service owners so they can make any technical changes required to give you access.
Get a PSN compliance certificate
The PSN team will review your compliance submission and then write to let you know if you’ve passed the compliance tests. If you have been successful you’ll receive a PSN Compliance Certificate for your organisation. We aim to process these requests within 15 days. Read the PSN customer compliance guide or [PSN service provider compliance guide[(/government/admin/detailed-guides/409824) for more information.
Your connectivity supplier will do the physical installation and configuration of the PSN connectivity service. There can be a lead time of approximately 9 weeks between ordering the circuit to installation. You also need to confirm with your supplier that they have got Government Communications Network (GCN) connectivity. If they don’t you’re unlikely to be able to access other government services on the PSN.
If you have services bought through the GCF framework you need to complete and return a request for change (RFC) to our current core services provider, Vodafone. You need to complete this no later than 6 weeks before the date you want to transition. You will need your PSN IP address to complete the RFC form.
Your supplier will provide specific technical details about connecting to their network following an order. We have also set out below technical steps to follow to successfully connect to PSN.
You will need to configure your firewall to enable the new IP address scheme. The current recommended rule set is:
From | To | Protocol | Action | Comment |
Your proxy/NAT | PSN | HTTP (TCP:80) HTTP (TCP:8080) HTTPS (TCP443) | Allow | Enable outbound access to applications within the PSN using HTTP & HTTPS |
PSN | Your web services | HTTP (TCP:80) HTTPS (TCP:443) | Allow | Enable outbound access to applications within the PSN using HTTP & HTTPS |
PSN | Your email servers | SMTP (TCP:25) | Allow | Enable inbound email from PSN |
Your mail servers | PSN | SMTP (TCP:25) | Allow | Enable outbound email from your network to the PSN |
Your DNS servers | PSN DNS servers | DNS (UDP:53) DNS (TCP:53) | Allow | Allow queries to the PSN DNS servers |
Your NTP servers | PSN NTP servers | NTP (UDP:123) | Allow | Allow queries to PSN NTP servers |
Any | Any | Any | Block | Default rule for all other traffic |
PSN provides the primary DNS servers and resolvers for the following domains: gcsx.gov.uk, gsi.gov.uk, gsx.gov.uk, gse.gov.uk. The IP addresses of the PSN DNS resolvers that you should configure on your DNS servers are 51.33.255.42 and 51.33.255.58, both accessible using DNS on UDP Port 53. Always use the PSN DNS resolvers, and let the PSN DNS resolvers forward any unresolved names to internet DNS servers.
These other domain names are also available for forwarding to the PSN DNS servers:
- psn-service.net
- psn-z-service.net
- internalpublicservicesnetwork.service.gov.uk
- registertovote.service.gov.uk
- psn.skyscapecloud.com
No central Network Time Protocol (NTP) service is provided. You can either continue to use a service provided from the GCF framework or request this from your DNSP.
IP routing
You need to configure your firewalls so your users can route to the IP address on the network that they need to reach. Each of your service providers will confirm with you what IP address ranges their services are on. If you still can’t route to these IP address, you need to work with your DNSP and the provider of the service you are trying to reach.
These networks may require additional routing configuration:
Address Block | Community |
51.130.0.0/18 | PSN IL2 Community |
51.33.255.32/27 | PSN IL2 DNS Service |
51.62.0.0/18 | GCSX Community |
51.63.224.0/24 51.63.225.0/24 | GCSX Hosting |
51.63.0.0/16 | GCF Summary (GSI, GSX & GSE) |
51.65.224.0/19 51.67.224.0/19 | CJX Community |
51.64.0.0/16 | SCN Community |
155.231.0.0/16 194.189.111.96/27 | N3 SPINE (only applicable if you have access to N3) |
You need to identify all services and organisations that you communicate with. Some of these may be outside the PSN. Email is allowed to move between these networks but for other services, like web traffic (HTML), you’ll need:
- the provider of the service or network to give you permission.
- a public sector interconnect provider to enable routing between your organisation and the required service or network
- the provider of the service to enable access to the specific services you need.
- your local IT team and your connectivity service provider to make sure that you can route to the destination IP address ranges, as described in IP Routing
- your local IT team and the external service provider to configure the required services appropriate to your users’ needs
Vodafone is the only public sector interconnect provider. You should use the GCF request for change form for this, and ensure that it’s submitted to Vodafone by the authority for the service you need to access.
The external networks that you can currently access through this route are:
- NHS N3 network
- European Council of Ministers network
- Criminal Justice Extranet (CJX)
- Police National Network (PNN)
- Criminal Justice Secure Mail
- Various European Union Government Intranets (TESTA)
Test your new connection
Make sure you can access the services you use. Email the PSN transition team for help with connectivity testing and a service take-on guide for PSN core services.
You should receive a service take-on guide from each PSN connectivity or service provider you use.
You should run your old and new network services at the same time until you’re happy to submit a cease order with your previous supplier.