# Connections and Authentication > Complete dossiers for 45 core PostgreSQL settings in Connections and Authentication. --- Dossier URLs remain flat; this category exists only to organize browsing and the sidebar. --- Section pages: - [authentication_timeout](/parameters/authentication-timeout/): authentication_timeout is the PostgreSQL setting that defines the maximum allowed time to complete client authentication. - [bonjour](/parameters/bonjour/): bonjour is the PostgreSQL setting that controls whether PostgreSQL enables advertising the server via Bonjour. - [bonjour_name](/parameters/bonjour-name/): bonjour_name is the PostgreSQL setting that defines the Bonjour service name. - [client_connection_check_interval](/parameters/client-connection-check-interval/): client_connection_check_interval is the PostgreSQL setting that defines the time interval between checks for disconnection while running queries. - [db_user_namespace](/parameters/db-user-namespace/): db_user_namespace is the PostgreSQL setting that controls whether PostgreSQL enables per-database user names. - [gss_accept_delegation](/parameters/gss-accept-delegation/): gss_accept_delegation is the PostgreSQL setting that defines whether GSSAPI delegation should be accepted from the client. - [krb_caseins_users](/parameters/krb-caseins-users/): krb_caseins_users is the PostgreSQL setting that defines whether Kerberos and GSSAPI user names should be treated as case-insensitive. - [krb_server_keyfile](/parameters/krb-server-keyfile/): krb_server_keyfile is the PostgreSQL setting that defines the location of the Kerberos server key file. - [krb_srvname](/parameters/krb-srvname/): krb_srvname — Sets the name of the Kerberos service. Observed in PG9.0–9.3; its last measured boot default is postgres in PG9.3, with sighup context. It was removed in PG9.4. - [listen_addresses](/parameters/listen-addresses/): listen_addresses is the PostgreSQL setting that defines the host name or IP address(es) to listen to. - [max_connections](/parameters/max-connections/): The startup-time ceiling on concurrent PostgreSQL client connections and a sizing input for several shared resources. - [md5_password_warnings](/parameters/md5-password-warnings/): md5_password_warnings is the PostgreSQL setting that controls whether PostgreSQL enables deprecation warnings for MD5 passwords. - [oauth_validator_libraries](/parameters/oauth-validator-libraries/): oauth_validator_libraries is the PostgreSQL setting that lists libraries that may be called to validate OAuth v2 bearer tokens. - [password_encryption](/parameters/password-encryption/): password_encryption is the PostgreSQL setting that chooses the algorithm for encrypting passwords. - [password_expiration_warning_threshold](/parameters/password-expiration-warning-threshold/): password_expiration_warning_threshold — Threshold for password expiration warnings. Observed in PG19 Beta 3; its last measured boot default is 7 d in PG19 Beta 3, with sighup context. This is a beta-snapshot fact and can change before PostgreSQL 19 GA. - [port](/parameters/port/): port is the PostgreSQL setting that defines the TCP port the server listens on. - [reserved_connections](/parameters/reserved-connections/): reserved_connections is the PostgreSQL setting that defines the number of connection slots reserved for roles with privileges of pg_use_reserved_connections. - [scram_iterations](/parameters/scram-iterations/): scram_iterations is the PostgreSQL setting that defines the iteration count for SCRAM secret generation. - [ssl](/parameters/ssl/): ssl is the PostgreSQL setting that controls whether PostgreSQL enables SSL connections. - [ssl_ca_file](/parameters/ssl-ca-file/): ssl_ca_file is the PostgreSQL setting that identifies the location of the SSL certificate authority file. - [ssl_cert_file](/parameters/ssl-cert-file/): ssl_cert_file is the PostgreSQL setting that identifies the location of the SSL server certificate file. - [ssl_ciphers](/parameters/ssl-ciphers/): ssl_ciphers is the PostgreSQL setting that defines the list of allowed TLSv1.2 (and lower) ciphers. - [ssl_crl_dir](/parameters/ssl-crl-dir/): ssl_crl_dir is the PostgreSQL setting that identifies the location of the SSL certificate revocation list directory. - [ssl_crl_file](/parameters/ssl-crl-file/): ssl_crl_file is the PostgreSQL setting that identifies the location of the SSL certificate revocation list file. - [ssl_dh_params_file](/parameters/ssl-dh-params-file/): ssl_dh_params_file is the PostgreSQL setting that identifies the location of the SSL DH parameters file. - [ssl_ecdh_curve](/parameters/ssl-ecdh-curve/): ssl_ecdh_curve is the PostgreSQL setting that defines the curve to use for ECDH. - [ssl_groups](/parameters/ssl-groups/): ssl_groups is the PostgreSQL setting that defines the group(s) to use for Diffie-Hellman key exchange. - [ssl_key_file](/parameters/ssl-key-file/): ssl_key_file is the PostgreSQL setting that identifies the location of the SSL server private key file. - [ssl_max_protocol_version](/parameters/ssl-max-protocol-version/): ssl_max_protocol_version is the PostgreSQL setting that defines the maximum SSL/TLS protocol version to use. - [ssl_min_protocol_version](/parameters/ssl-min-protocol-version/): ssl_min_protocol_version is the PostgreSQL setting that defines the minimum SSL/TLS protocol version to use. - [ssl_passphrase_command](/parameters/ssl-passphrase-command/): ssl_passphrase_command is the PostgreSQL setting that defines the command to obtain passphrases for SSL. - [ssl_passphrase_command_supports_reload](/parameters/ssl-passphrase-command-supports-reload/): ssl_passphrase_command_supports_reload is the PostgreSQL setting that controls whether "ssl_passphrase_command" is called during server reload. - [ssl_prefer_server_ciphers](/parameters/ssl-prefer-server-ciphers/): ssl_prefer_server_ciphers is the PostgreSQL setting that gives priority to server ciphersuite order. - [ssl_renegotiation_limit](/parameters/ssl-renegotiation-limit/): ssl_renegotiation_limit — Set the amount of traffic to send and receive before renegotiating the encryption keys. Observed in PG9.0–9.4; its last measured boot default is 0 B in PG9.4, with user context. It was removed in PG9.5. - [ssl_sni](/parameters/ssl-sni/): ssl_sni — Sets whether to interpret SNI extensions in SSL connections. Observed in PG19 Beta 3; its last measured boot default is off in PG19 Beta 3, with sighup context. This is a beta-snapshot fact and can change before PostgreSQL 19 GA. - [ssl_tls13_ciphers](/parameters/ssl-tls13-ciphers/): ssl_tls13_ciphers is the PostgreSQL setting that defines the list of allowed TLSv1.3 cipher suites. - [superuser_reserved_connections](/parameters/superuser-reserved-connections/): superuser_reserved_connections is the PostgreSQL setting that defines the number of connection slots reserved for superusers. - [tcp_keepalives_count](/parameters/tcp-keepalives-count/): tcp_keepalives_count is the PostgreSQL setting that defines the maximum number of TCP keepalive retransmits. - [tcp_keepalives_idle](/parameters/tcp-keepalives-idle/): tcp_keepalives_idle is the PostgreSQL setting that defines the interval between issuing TCP keepalives. - [tcp_keepalives_interval](/parameters/tcp-keepalives-interval/): tcp_keepalives_interval is the PostgreSQL setting that defines the interval between TCP keepalive retransmits. - [tcp_user_timeout](/parameters/tcp-user-timeout/): tcp_user_timeout is the PostgreSQL setting that defines the TCP user timeout. - [unix_socket_directories](/parameters/unix-socket-directories/): unix_socket_directories is the PostgreSQL setting that defines the directories where Unix-domain sockets will be created. - [unix_socket_directory](/parameters/unix-socket-directory/): unix_socket_directory — Sets the directory where the Unix-domain socket will be created. Observed in PG9.0–9.2; its last measured boot default is empty string in PG9.2, with postmaster context. It was removed in PG9.3. - [unix_socket_group](/parameters/unix-socket-group/): unix_socket_group is the PostgreSQL setting that defines the owning group of the Unix-domain socket. - [unix_socket_permissions](/parameters/unix-socket-permissions/): unix_socket_permissions is the PostgreSQL setting that defines the access permissions of the Unix-domain socket.