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= Running Client Nodes Behind NAT

If your client nodes are deployed behind a NAT, the server nodes won't be able to establish connection with the clients because of the limitations of the communication protocol.
This includes deployment cases when client nodes are running in virtual environments (like Kubernetes) and the server nodes are deployed elsewhere.

For cases like this, you need to enable a special mode of communication:

[tabs]
--
tab:XML[]

[source, xml]
----
include::code-snippets/xml/client-behind-nat.xml[tags=ignite-config;!discovery,indent=0]
----
tab:Java[]
[source, java]
----
include::{javaCodeDir}/Discovery.java[tags=client-behind-nat,indent=0]
----
tab:C#/.NET[]

tab:C++[unsupported]
--

== Limitations

* This mode cannot be used when `TcpCommunicationSpi.usePairedConnections = true` on both server and client nodes.

* Peer class loading for link:key-value-api/continuous-queries[continuous queries (transformers and filters)] does not work when a continuous query is started from a client node `forceClientToServerConnections = true`.
You will need to add the corresponding classes to the classpath of every server node.

* This property can only be used on client nodes. This limitation will be addressed in the future releases.