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sslsni

If set to 1 (default), libpq sets the TLS extension “ Server Name Indication ” ( SNI ) on SSL-enabled connections. By setting this parameter to 0, this is turned off.

Reading PG 18·Select a recorded version

Client library
libpq 18.6
Manual definition
Documented
Source environment fallback
PGSSLSNI
Compiled fallback expression
"1"
default evidence
If set to 1 (default), libpq sets the TLS extension “ Server Name Indication ” ( SNI ) on SSL-enabled connections. By setting this parameter to 0, this is turned off.
documented
true
environment
map[description:PGSSLSNI behaves the same as the sslsni connection parameter. name:PGSSLSNI source_url:/docs/18/libpq-envars.html]
keyword
sslsni
manual path
libpq-connect.html#LIBPQ-CONNECT-SSLSNI
signature
sslsni

Definition PG 18

sslsni

If set to 1 (default), libpq sets the TLS extension “Server Name Indication” (SNI) on SSL-enabled connections. By setting this parameter to 0, this is turned off.

The Server Name Indication can be used by SSL-aware proxies to route connections without having to decrypt the SSL stream. (Note that unless the proxy is aware of the PostgreSQL protocol handshake this would require setting sslnegotiation to direct.) However, SNI makes the destination host name appear in cleartext in the network traffic, so it might be undesirable in some cases.

Environment fallback

VariableDocumented behavior
PGSSLSNIPGSSLSNI behaves the same as the sslsni connection parameter.

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Complete source facts

precedence evidence

The following environment variables can be used to select default connection parameter values, which will be used by PQconnectdb , PQsetdbLogin and PQsetdb if no value is directly specified by the calling code. These are useful to avoid hard-coding database connection information into simple client applications, for example., Service names can be defined in either a per-user service file or a system-wide file. If the same service name exists in both the user and the system file, the user file takes precedence. By default, the per-user service file is named ~/.pg_service.conf . On Microsoft Windows, it is named %APPDATA%\postgresql\.pg_service.conf (where %APPDATA% refers to the Application Data subdirectory in the user's profile). A different file name can be specified by setting the environment variable PGSERVICEFILE . The system-wide file is named pg_service.conf . By default it is sought in the etc directory of the PostgreSQL installation (use pg_config --sysconfdir to identify this directory precisely). Another directory, but not a different file name, can be specified by setting the environment variable PGSYSCONFDIR ., Connection parameters obtained from a service file are combined with parameters obtained from other sources. A service file setting overrides the corresponding environment variable, and in turn can be overridden by a value given directly in the connection string. For example, using the above service file, a connection string service=mydb port=5434 will use host somehost , port 5434 , user admin , and other parameters as set by environment variables or built-in defaults.

source option

{"compiled_default_expression":"\"1\"","declaration":"\"sslsni\", \"PGSSLSNI\", \"1\", NULL, \"SSL-SNI\", \"\", 1, offsetof(struct pg_conn, sslsni)","environment":"PGSSLSNI","keyword":"sslsni","source_notes":[]}

Source references

Full definition and evidence JSON

Definition sources

center · PostgreSQL 18 · ee8d1a3612338fd9adf250730cb640fcc5233b5491337cc00a316a44e3a0b9f8

Text language: en · ee8d1a3612338fd9adf250730cb640fcc5233b5491337cc00a316a44e3a0b9f8