ABB NETA-21, User Manual

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44 Program features
HTTP
The HTTP (Hypertext Transfer Protocol) is used to serve web pages using the HTML
(Hypertext Markup Language) and Javascript. To use the NETA-21 web interface you
need a browser supporting Javascript and cookies (see
Hardware and software
requirements of the PC ). External plug-ins, such as Java or Flash, are not required.
It is recommended to use HTTP only with a direct cable connection to the NETA-21. For all
other purposes it is recommended to use the secure HTTPS. To switch from HTTP to
HTTPS edit the address from http://192.168.230.1 to https://192.168.230.1. You can also
do this by checking the
Prefer HTTPS check box in Network services .
HTTPS URLs use port 443 by default, whereas HTTP URLs use port 80 by default.
HTTPS
The Hypertext Transfer Protocol Secure (HTTPS) is a combination of the HTTP with an
added encryption layer of SSL/TLS protocols to create a secure channel over an insecure
network, provided that adequate cipher suites are used and that the server certificate is
verified and trusted. The HTTPS is supported by all popular browsers.
Note: Although the HTTPS encrypts everything, including the URL, an eavesdropper can
still observe the host name and port of the URL because they are part of TCP/IP packets
to establish and maintain the connection. This means that an eavesdropper or attacker
can know that a connection is taking place between the two parties, get the domain name
and IP addresses, through which he can see the sites the host is connect to, the amount of
time spend using a site, and the amount of information uploaded or downloaded on the
particular site.

HTTPS certificate
The NETA-21 HTTPS uses a self-signed certificate which is uniquely generated per each
NETA-21 tool. The factory reset of the NETA-21 can also reset the self-signed certificate
and generate a new one (while, eg, a firmware update keeps the certificate unchanged).
Most browsers display a warning if they receive an invalid or a self-signed certificate.
When you connect an older browser to a site with an invalid certificate the browser shows
you a dialog box asking if you want to continue. Newer browsers display a warning across
the entire window and also prominently display the site's security information in the
address bar. Extended validation certificates turn the address bar green in newer
browsers. Most browsers also display a warning when you visit a site that contains a
mixture of encrypted and unencrypted content.
From the NETA-21 firmware version 2.13 onwards you can install a customized HTTPS
site certificate to each NETA-21. The installation requires than an Apache 2 compatible
apache.pem certificate file is generated on the PC and saved to folder "cert” in the SD
memory card. Create a “cert” folder, if the “cert” folder does not exist. The customized
certificate will be taken to use after a reboot or power-up of the NETA-21. A valid certificate
is taken into use and removed from the memory card for security reasons.