1ssl(7) Erlang Application Definition ssl(7)
2
6 ssl - The ssl application provides secure communication over
7 sockets.
8
10 The ssl application is an implementation of the SSL, TLS and DTLS pro‐
11 tocols in Erlang.
12 For current statement of standards compliance see the User's Guide.
14
16 The SSL application uses the public_key, asn1 and Crypto application to
17 handle public keys and encryption, hence these applications must be
18 loaded for the SSL application to work. In an embedded environment this
19 means they must be started with application:start/[1,2] before the SSL
20 application is started.
21
23 The application environment configuration parameters in this section
24 are defined for the SSL application. For more information about config‐
25 uration parameters, see the application(3) manual page in Kernel.
26 The environment parameters can be set on the command line, for example:
28 erl -ssl protocol_version "['tlsv1.2', 'tlsv1.1']"
30 protocol_version = ssl:ssl_tls_protocol()<optional>:
32 Protocol supported by started clients and servers. If this option
33 is not set, it defaults to all TLS protocols currently supported by
34 the SSL application. This option can be overridden by the version
35 option to ssl:connect/[2,3] and ssl:listen/2.
36 dtls_protocol_version = ssl:dtls_protocol()<optional>:
38 Protocol supported by started clients and servers. If this option
39 is not set, it defaults to all DTLS protocols currently supported
40 by the SSL application. This option can be overridden by the ver‐
41 sion option to ssl:connect/[2,3] and ssl:listen/2.
42 session_lifetime = integer() <optional>:
44 Maximum lifetime of the session data in seconds. Defaults to 24
45 hours which is the maximum recommended lifetime by RFC 5246. How‐
46 ever sessions may be invalidated earlier due to the maximum limita‐
47 tion of the session cache table.
48 session_cb = atom() <optional>:
50 Name of the session cache callback module that implements the
51 ssl_session_cache_api behavior. Defaults to ssl_session_cache.
52 session_cb_init_args = proplist:proplist() <optional>:
54 List of extra user-defined arguments to the init function in the
55 session cache callback module. Defaults to [].
56 session_cache_client_max = integer() <optional>
58 : Limits the growth of the clients session cache, that is how many
59 sessions towards servers that are cached to be used by new client
60 connections. If the maximum number of sessions is reached, the cur‐
61 rent cache entries will be invalidated regardless of their remain‐
62 ing lifetime. Defaults to 1000. Recommended ssl-8.2.1 or later for
63 this option to work as intended.
64 session_cache_server_max = integer() <optional>:
66 Limits the growth of the servers session cache, that is how many
67 client sessions are cached by the server. If the maximum number of
68 sessions is reached, the current cache entries will be invalidated
69 regardless of their remaining lifetime. Defaults to 1000. Recom‐
70 mended ssl-8.2.1 or later for this option to work as intended.
71 ssl_pem_cache_clean = integer() <optional>:
73 Number of milliseconds between PEM cache validations. Defaults to 2
74 minutes.ssl:clear_pem_cache/0
75 bypass_pem_cache = boolean() <optional>:
77 Introduced in ssl-8.0.2. Disables the PEM-cache. Can be used as a
78 workaround for the PEM-cache bottleneck before ssl-8.1.1. Defaults
79 to false.
80 alert_timeout = integer() <optional>:
82 Number of milliseconds between sending of a fatal alert and closing
83 the connection. Waiting a little while improves the peers chances
84 to properly receiving the alert so it may shutdown gracefully.
85 Defaults to 5000 milliseconds.
86 internal_active_n = integer() <optional>:
88 For TLS connections this value is used to handle the internal
89 socket. As the implementation was changed from an active once to an
90 active N behavior (N = 100), for performance reasons, this option
91 exist for possible tweaking or restoring of the old behavior
92 (internal_active_n = 1) in unforeseen scenarios. The option will
93 not affect erlang distribution over TLS that will always run in
94 active N mode. Added in ssl-9.1 (OTP-21.2).
95
97 The SSL application uses the default OTP error logger to log unexpected
98 errors and TLS/DTLS alerts. The logging of TLS/DTLS alerts may be
99 turned off with the log_alert option.
100
102 application(3)
103Ericsson AB ssl 9.4 ssl(7)