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Network Functions



No external libraries are needed to build this extension.


There is no installation needed to use these functions; they are part of the PHP core.

Runtime Configuration

The behaviour of these functions is affected by settings in php.ini.

Table 198. Network Configuration Options


For further details and definitions of the PHP_INI_* constants, see the Appendix I, php.ini directives.

Here's a short explanation of the configuration directives.

define_syslog_variables boolean

Whether or not to define the various syslog variables (e.g. $LOG_PID, $LOG_CRON, etc.). Turning it off is a good idea performance-wise. At runtime, you can define these variables by calling define_syslog_variables().

Resource Types

This extension defines a file pointer resource returned by fsockopen() and pfsockopen().

Predefined Constants

The constants below are always available as part of the PHP core.

Table 199. openlog() Options

LOG_CONS if there is an error while sending data to the system logger, write directly to the system console
LOG_NDELAY open the connection to the logger immediately
LOG_ODELAY (default) delay opening the connection until the first message is logged
LOG_PERRORprint log message also to standard error
LOG_PIDinclude PID with each message

Table 200. openlog() Facilities

LOG_AUTH security/authorization messages (use LOG_AUTHPRIV instead in systems where that constant is defined)
LOG_AUTHPRIVsecurity/authorization messages (private)
LOG_CRONclock daemon (cron and at)
LOG_DAEMONother system daemons
LOG_KERNkernel messages
LOG_LOCAL0 ... LOG_LOCAL7reserved for local use, these are not available in Windows
LOG_LPRline printer subsystem
LOG_MAILmail subsystem
LOG_NEWSUSENET news subsystem
LOG_SYSLOGmessages generated internally by syslogd
LOG_USERgeneric user-level messages
LOG_UUCPUUCP subsystem

Table 201. syslog() Priorities (in descending order)

LOG_EMERGsystem is unusable
LOG_ALERTaction must be taken immediately
LOG_CRITcritical conditions
LOG_ERRerror conditions
LOG_WARNINGwarning conditions
LOG_NOTICEnormal, but significant, condition
LOG_INFOinformational message
LOG_DEBUGdebug-level message

Table 202. dns_get_record() Options

DNS_AIPv4 Address Resource
DNS_MXMail Exchanger Resource
DNS_CNAMEAlias (Canonical Name) Resource
DNS_NSAuthoritative Name Server Resource
DNS_PTRPointer Resource
DNS_HINFOHost Info Resource (See IANA's » Operating System Names for the meaning of these values)
DNS_SOAStart of Authority Resource
DNS_TXTText Resource
DNS_ANYAny Resource Record. On most systems this returns all resource records, however it should not be counted upon for critical uses. Try DNS_ALL instead.
DNS_AAAAIPv6 Address Resource
DNS_ALLIteratively query the name server for each available record type.

Table of Contents

checkdnsrr — Check DNS records corresponding to a given Internet host name or IP address
closelog — Close connection to system logger
debugger_off — Disable internal PHP debugger (PHP 3)
debugger_on — Enable internal PHP debugger (PHP 3)
define_syslog_variables — Initializes all syslog related constants
dns_check_record — Alias of checkdnsrr()
dns_get_mx — Alias of getmxrr()
dns_get_record — Fetch DNS Resource Records associated with a hostname
fsockopen — Open Internet or Unix domain socket connection
gethostbyaddr — Get the Internet host name corresponding to a given IP address
gethostbyname — Get the IP address corresponding to a given Internet host name
gethostbynamel — Get a list of IP addresses corresponding to a given Internet host name
getmxrr — Get MX records corresponding to a given Internet host name
getprotobyname — Get protocol number associated with protocol name
getprotobynumber — Get protocol name associated with protocol number
getservbyname — Get port number associated with an Internet service and protocol
getservbyport — Get Internet service which corresponds to port and protocol
header — Send a raw HTTP header
headers_list — Returns a list of response headers sent (or ready to send)
headers_sent — Checks if or where headers have been sent
inet_ntop — Converts a packed internet address to a human readable representation
inet_pton — Converts a human readable IP address to its packed in_addr representation
ip2long — Converts a string containing an (IPv4) Internet Protocol dotted address into a proper address
long2ip — Converts an (IPv4) Internet network address into a string in Internet standard dotted format
openlog — Open connection to system logger
pfsockopen — Open persistent Internet or Unix domain socket connection
setcookie — Send a cookie
setrawcookie — Send a cookie without urlencoding the cookie value
socket_get_status — Alias of stream_get_meta_data()
socket_set_blocking — Alias of stream_set_blocking()
socket_set_timeout — Alias of stream_set_timeout()
syslog — Generate a system log message