NetworkManager and nm-tool
If you wish to check the speed of network interfaces on a
CentOS
Linux system, if the nm-tool
utility, is installed, then you can use it to determine the speed of the
network ports.
$ nm-tool
NetworkManager Tool
State: disconnected
- Device: em1 ------------------------------------------------------------------
Type: Wired
Driver: bnx2
State: unmanaged
Default: no
HW Address: D4:AE:52:CD:0A:D4
Capabilities:
Carrier Detect: yes
Speed: 1000 Mb/s
Wired Properties
Carrier: on
- Device: em2 ------------------------------------------------------------------
Type: Wired
Driver: bnx2
State: unmanaged
Default: no
HW Address: D4:AE:52:CD:0A:D5
Capabilities:
Carrier Detect: yes
Wired Properties
Carrier: off
$If it is installed, the nm-tool program will likely be in /usr/bin
. It is part of the NetworkManager package.
[ More Info ]
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Determining the version of CentOS on a system
If you are logged into a CentOS Linux system, there are a few ways you can determine
the version of CentOS running on the system from a
command-line interface (CLI), i.e., a
shell
prompt.
In the /etc directory, there should be a
/etc/centos-release file containing information on the version
of CentOS.
$ ls -l /etc/*elease
-rw-r--r-- 1 root root 27 Mar 28 2017 /etc/centos-release
-rw-r--r--. 1 root root 152 Nov 25 2013 /etc/lsb-release
lrwxrwxrwx 1 root root 14 Apr 20 2017 /etc/redhat-release -> centos-release
lrwxrwxrwx 1 root root 14 Apr 20 2017 /etc/system-release -> centos-release
$ cat /etc/*elease
CentOS release 6.9 (Final)
LSB_VERSION=base-4.0-amd64:base-4.0-noarch:core-4.0-amd64:core-4.0-noarch:graphi
cs-4.0-amd64:graphics-4.0-noarch:printing-4.0-amd64:printing-4.0-noarch
CentOS release 6.9 (Final)
CentOS release 6.9 (Final)
$
To just see the version number, you can use one of the
grep commands below.
$ grep -oE '[0-9]+\.[0-9]+' /etc/redhat-release
6.9
$ grep -oE '[0-9]+\.[0-9]+' /etc/centos-release
6.9
$
[ More Info ]
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Determining if a site has implemented HTTP Strict Transport Security (HSTS)
HTTP Strict Transport Security (HSTS) is a security
mechanism used by some websites to ensure that
HTTP Secure (HTTPS)
is always used by visitors to the site even should some intermediate
system between the visitor's browser and the website attempt a
man-in-the-middle (MITM) attack to
downgrade the communications protocol to the unencrypted
Hypertext
Transfer Protocol (HTTP). The HSTS specification was published as
Request for Comments (RFC) 6797
on November 19, 2012. You can tell whether a site has implemented
HSTS by establishing a telnet connection to port 80, the
well-known port for HTTP connections. E.g.:
$ telnet example.com 80
Trying 192.168.141.50...
Connected to example.com
Escape character is '^]'.
HEAD / HTTP/1.1
HOST: example.com
HTTP/1.1 301 Moved Permanently
Date: Wed, 06 Dec 2017 02:56:57 GMT
Server: Apache
X-Frame-Options: SAMEORIGIN
Strict-Transport-Security: max-age=31536000; includeSubDomains
Location: https://example.com/
Connection: close
Content-Type: text/html; charset=iso-8859-1
Connection closed by foreign host.
$
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