App-26
IM DL850E-01EN
Appendix 7 TCP and UDP Port Numbers
The TCP and UDP port numbers that are used on the Ethernet interface of the DL850E/DL850EV are listed
below.
TCP Port Numbers
Port Number Description
Used For
20
File Transfer [Default Data]
FTP server, FTP client,
*
and a portion of the
Web server
21
File Transfer [Control]
FTP server, FTP client, and a portion of the
Web server
25
Simple Mail Transfer Protocol
SMTP client
80
World Wide Web HTT
Web server and WebDAV server
515
−
LPR client
111
−
Instrument control through the Ethernet
interface
UDP Port Numbers
Port Number Description
Used For
67
Bootstrap Protocol Server
DHCP client
68
Bootstrap Protocol Client
(listen port)
123
Network Time Protocol
SNTP client
* The port number when FTP passive mode is disabled. When FTP passive mode is enabled, you can set any
port number. When FTP passive mode is disabled, connections are established from the server. If you are
connecting the DL850E/DL850EV from behind a firewall, enable FTP passive mode.
Appendix