---
name: "DTLS_get_data_mtu"
section: "3ssl"
platform: "linux"
package: "openssl"
version: "3.6.5-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/DTLS_get_data_mtu"
---

# DTLS\_get\_data\_mtu(3ssl)

Get maximum data payload size

## NAME

DTLS\_get\_data\_mtu - Get maximum data payload size

## SYNOPSIS

```
 #include <openssl/ssl.h>
 size_t DTLS_get_data_mtu(const SSL *ssl);
```

## DESCRIPTION

This function obtains the maximum data payload size for the established DTLS connection **ssl**, based on the DTLS record MTU and the overhead of the DTLS record header, encryption and authentication currently in use.

## RETURN VALUES

Returns the maximum data payload size on success, or 0 on failure.

## HISTORY

The **DTLS\_get\_data\_mtu()** function was added in OpenSSL 1.1.1.

## COPYRIGHT

Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License").  You may not use this file except in compliance with the License.  You can obtain a copy in the file LICENSE in the source distribution or at \<https://www.openssl.org/source/license.html\>.