---
title:  Implementing Authentication Expiry
---

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Authentication expiry is supported only with client connections.
The use of expirable credentials is most common when used in combination with token-based authentication and authorization.
Authentication expiry makes it possible for cluster administrators to limit the life span of client
connections within the cluster.

Client connections are notified of expiry by `AuthenticationExpiredException`,
which is thrown in the implementations of `SecurityManager.authenticate` or `SecurityManager.authorize`.

Upon receiving the AuthenticationExpiredException, clients will make one automatic attempt to gather new credentials and reconnect (AuthInitialize.getCredentials()).
Upon receiving a second `AuthenticationExpiredException`
the exception is thrown back to the user to handle. There are some differences in
behavior between older and newer clients.

**Support for Automatic	Reconnect**

Client version | single user ops | multi user ops | single user CQ/RI | multi user CQ/RI
--- | :---: | :---: | :---: | :---:
Geode 1.15 and later | Y  | Y  | Y | N
older than Geode 1.15 | Y  | Y  | N | N

``` pre
Y = supported
N = not supported
```

Clients older than version 1.15 will also be able to do an automatic reconnect unless the connection
is one of the following types where the exception will always be propagated up the chain:

* multi-user client mode
* event-dispatching (CQ and registered interest)

## <a id="authentication_expiry_considerations"></a>Authentication Expiry Considerations

The common cycle for authentication and authorization is the following:

```pre
AuthInitialize.getCredentials(...) -> SecurityManager.authenticate(...) -> SecurityManager.authorize(...)
```

In case of the use of an external token provider we assume that this token provider will be asked for
a token in the `AuthInitialize.getCredentials()` call. A token provider can return existing tokens (which are about to expire) for
a given user, so it is recommended that implementers of the `AuthInitialize` and `SecurityManager`
interfaces take imminent timeout and token refresh in consideration to avoid receiving multiple
unintended `AuthenticationExpiredException`s in a row and having to deal with the propagation of these
exceptions.