Migrating from IPv4 to IPv6
Overview
If you currently use an IPv4 infrastructure for network communications, there is a general recommendation within the IT industry to move to an IPv6 infrastructure. One of the main reasons is that the number of available new IPv4 addresses has reduced to practically zero, whereas new IPv6 addresses are expected to be plentiful for a long time to come.
Universal Messaging can support an environment that uses only IPv4, or an environment that uses only IPv6, or an environment that supports a combination of IPv4 and IPv6. Universal Messaging is written in Java, which by design works seamlessly with IPv4 and IPv6 in parallel (the mechanism is called dual stack). If the underlying operating system and network infrastructure support dual stack, then the Universal Messaging server socket can communicate with both IPv4 and IPv6 clients at the transport layer without any changes in the source code or settings.
The server sockets that are expected to serve both IPv4 and IPv6 clients should be bound to "0.0.0.0" or "::0", and not to any specific IPv4 or IPv6 address.
The following setups are supported:
If your environment uses only IPv4 addressing, Universal Messaging will continue to support your environment. There is no technical requirement to move to IPv6.
If you intend to migrate your entire environment to IPv6 addressing, Universal Messaging will in most cases continue to work after the migration without manual reconfiguration, but there are some points to watch out for. See the section
Migrating to IPv6 below for details.
If you intend to use IPv4 addressing for some clients, and IPv6 addressing for other clients, this is also supported in Universal Messaging.
Migrating to IPv6
If you plan to migrate all of your clients from IPv4 to IPv6 addressing, Universal Messaging will in most cases work with the new IPv6 clients without needing any manual configuration changes. However, you need to check for any hard-coded IPv4 addresses in the locations mentioned below and update them accordingly before you activate the IPv6 environment:
The hosts file Check the entries in the hosts file. If required, map the host name to the required IPv6 address. On Linux, the hosts file is /etc/hosts , and on Windows it is typically C:\Windows\System32\drivers\etc\hosts.
The
Server_Common.conf file
Check if Server_Common.conf uses a specific IPv4 address for the default adapter. If so, do the following:
Change the default adapter to "0.0.0.0" or "::0" or hostname as per the requirement.
Take a backup of
adapters.nst, then delete
adapters.nst.
The file adapters.nst is a binary file that contains the interface details of the realm server. It is present in <InstallDir>/UniversalMessaging/server/<InstanceName>/data/RealmSpecific.
Restart the server. This will create a new
adapters.nst file.
Also, before migrating to IPv6, check if your Universal Messaging server setup uses any other interface that was created using a specific IPv4 address. If you do not intend to support the IPv4 address any more after migration, you need to delete the interface. If, however, the IPv4 address will still be valid after migration, the interface does not need to be deleted, as Universal Messaging supports IPv4 and IPv6 at the same time.
To ensure that all of the IPv4 interface addresses that you wish to convert in a Universal Messaging realm have indeed been converted to IPv6 addresses, we suggest that you proceed as follows:
1. Export the current realm configuration to an XML file.
2. In the XML file, if there are any hard-coded IPv4 addresses that you wish to migrate, change them to either the host name or the corresponding IPv6 address.
3. If you made any changes in the XML file, import the XML file in order to update the realm to the new configuration. If you made no changes in the XML file, you can of course omit this step.
The instructions for exporting and importing a realm are given in the section
Exporting and Importing Realm XML Configurations .