PORT Sensor

The PORT sensor simply tries to connect to a server on a specific port number. If the server accepts the request to open the port IPCheck Server Monitor closes the port and regards this sensor as UP. Parameters include:

·      PORT—the port number of the service you want to monitor (see below)

Using PORT sensors it is possible to check the basic availability of any TCP service by trying to connect to its port.

Since the PORT sensor does not check whether the server reacts according to any protocols defined for a service it is recommended to use protocol based sensors whenever possible (e.g. by using the various other sensors included with IPCheck Server Monitor or by creating your own using the CUSTOM sensors). There are several services that still accept requests even though they do not send back correct information when they fail.

Some ports have numbers that are preassigned to them by the IANA for specific services (e.g. port 80 is usually used for HTTP traffic in the World Wide Web), and these are known as well-known ports (specified in RFC 1700).

Here is a list of well-known ports:

 

·      7 ECHO (used for PING)

·      20 FTP -- Data

·      21 FTP -- Control

·      22 SSH Remote Login Protocol

·      23 Telnet

·      25 Simple Mail Transfer Protocol (SMTP)

·      37 Time

·      42 Host Name Server (Nameserv)

·      43 WhoIs

·      53 Domain Name System (DNS)

·      69 Trivial File Transfer Protocol (TFTP)

·      70 Gopher Services

·      79 Finger

·      80 HTTP

·      103 X.400 Standard

·      108 SNA Gateway Access Server

·      109 POP2

·      110 POP3

·      115 Simple File Transfer Protocol (SFTP)

·      118 SQL Services

·      119 Newsgroup (NNTP)

·      137 NetBIOS Name Service

·      139 NetBIOS Datagram Service

·      143 Interim Mail Access Protocol (IMAP)

·      150 NetBIOS Session Service

·      156 SQL Server

·      161 SNMP

·      179 Border Gateway Protocol (BGP)

·      194 Internet Relay Chat (IRC)

·      197 Directory Location Service (DLS)

·      389 Lightweight Directory Access Protocol (LDAP)

·      396 Novell Netware over IP

·      443 HTTPS

·      444 Simple Network Paging Protocol (SNPP)

·      445 Microsoft-DS

·      458 Apple QuickTime

·      546 DHCP Client

·      547 DHCP Server

·      1080 Socks

For more information on port numbers please check RFC 1700: http://www.ietf.org/rfc/rfc1700.txt?number=1700

More:

What it means when the PORT sensor is up

What it means when the PORT sensor is down