Author Archives: Vyacheslav

nice and ionice. Process Priorities

nice – allows you to specify the priority of the processor performing various tasks, the range of priorities is -20 to 19, where 19 is the smallest, if not specified, then there will be a standard priority of 0. Convenient for example when packing data into archives so that this task does not load the server or when many processes need to be started, distributing the load, which occupy all CPU time.

Example of the execution of the command with the lowest priority:

nice -n 19 COMMAND

See the table of processes and their priorities as follows (column NI):

ps axl
ps -l

If the table is large, you can redirect the output of the command to Less and look at the page:

ps axl | less

To change the priority:

renice -n 19 PROCESS(PID)

Checking the default priority value (standard 0):

nice

ionice – allows you to specify the priority for I/O operations, for example, to reduce the load on the disk. The first class is from 1 to 3, then the priority is from 0 to 7, where 7 is the smallest.
There are three classes:
1) Real time – Preemptive without paying attention to other processes, indicating priorities from 0 to 7.
2) Best Effort — Standard with priorities from 0 to 7.
3) Idle — With idle time without priority.

Example of executing the command with the lowest I/O priority:

ionice -c2 -n7 COMMAND

To change the priority:

ionice -c2 -n7 -p PROCESS(PID)

To view the set priority:

ionice -p PROCESS(PID)

You can specify priorities at the same time via nice and ionice:

nice -n 19 ionice -c2 -n7 COMMAND

To specify high priorities, for example, you might need root permissions, this command should be executed as root user or added before the sudo command.

Solving the SSL problem “Connection is not secure – Parts of this page are not secure (such as images)”

I noticed once one site with a signed SSL certificate, a message from the Mozilla Firefox browser:

Connection is not secure – Parts of this page are not secure (such as images)

As it turned out, images from other sources were inserted on the site, so the connection can be considered not protected, and to solve this problem, you need to upload images to the current site and change the link on the pages, necessarily starting with https://.

If the site works on http:// and https://, and the pictures are on it, then the links should be changed for example from:

<img src="http://www.ixnfo.com/img.jpg">

to

<img src="/img.jpg">

Done.

Configuring Protected Ports on Cisco

On the test, I will configure the Cisco Catalyst WS-C3750-48TS-S.

And so, all ports are configured as access, except for the first Gigabit uplink port, it is configured as a trunk and the Internet on the client vlan with the tag comes to it.
We need all the ports on this switch to not see each other and see only the first gigabit ulink port.

To do this, connect to the switch and go into the configuration mode:

enable
configure terminal

Then, we issue the switchport protected command for all access ports:

interface range fastEthernet 1/0/1-48
switchport protected
interface range gigabitEthernet 1/0/2-4
switchport protected
exit
exit

Save the configuration:

write

Apparently interface gigabitEthernet 1/0/1 we did not touch.
Now the ports on which the switchport protected command is registered do not see the other ports on which this command is also registered, they see only the ports where it is not registered, that is, in our case the first gigabit ulink port, and it sees all the ports with the command and without.

Information about ports can be viewed by the command:

show interfaces NAME switchport

View full configuration:

show running-config

See also:
Port isolation on Huawei switches
Port isolation on the ZyXEL MES-3528 switch

Port isolation on the ZyXEL MES-3528 switch

On the test, I isolate the ports from each other, allowing traffic to go only to uplink (the port from which the Internet comes), I have it 25.

Let’s connect to the switch and see the current configuration:

show running-config

Now go into the configuration mode:

configure

Isolate the necessary ports, except the uplink port:

interface port-channel 1-24,26-28
vlan1q port-isolation
exit
exit

Save the configuration:

write memory

The ports on which the vlan1q port-isolation command is written do not see other ports with the same command, but see the ports without it and the switch CPU. Ports without the command vlan1q port-isolation see the ports with it and without it.

See also:
Port isolation on Huawei switches
Configuring Protected Ports on Cisco

Port isolation on Huawei switches

On the test I’ll take the Huawei Quidway S2326TP-EI and Huawei Quidway S3928P-EI switches, in which the uplink Gigabit Ethernet port 0/0/1 (the Internet comes to it), all other ports are in the same VLAN and you need to prevent them from seeing each other. To do this, execute the port-isolate enable command for each interface (port), except uplink GigabitEthernet 0/0/1.

We connect to the switch through the console or telnet and switch to the mode of elevated privileges:

system-view

We execute the command for interfaces:

interface Ethernet 0/0/1
port-isolate enable
interface Ethernet 0/0/2
port-isolate enable
interface Ethernet 0/0/3
port-isolate enable
etc.
interface Ethernet 0/0/24
port-isolate enable
quit
interface GigabitEthernet 0/0/2
port-isolate enable

For Huawei Quidway S3928P-EI there will be other commands:

interface Ethernet1/0/1
port isolate
interface Ethernet1/0/2
port isolate
...
interface GigabitEthernet 1/1/2
port isolate
interface GigabitEthernet 1/1/3
port isolate
interface GigabitEthernet 1/1/4
port isolate

Leave the interface setup mode:

quit

Let’s leave the regime of elevated privileges:

quit

Save the configuration:

save

Now the ports on which the port-isolate enable command is written do not see the other ports on which this command is also registered, they see only the ports where it is not registered, that is, in our case uplink port GigabitEthernet 0/0/1, and it, as on It does not have this command, it sees all the ports with the command and without.

See also:
Configuring the Huawei Quidway Switch S2326TP-EI
Configuring Port isolation on Cisco
Port isolation on the ZyXEL switch

Solving the error in Asterisk “File vm-newn does not exist in any format”

When I called a voicemail number, I noticed the following errors in the Asterisk console:

[Apr 10 17:08:01] WARNING[19135][C-00001cf4]: file.c:701 ast_openstream_full: File digits/1n does not exist in any format
[Apr 10 17:08:01] WARNING[19135][C-00001cf4]: file.c:1017 ast_streamfile: Unable to open digits/1n (format (ulaw)): No such file or directory
[Apr 10 17:08:01] WARNING[19135][C-00001cf4]: file.c:701 ast_openstream_full: File vm-newn does not exist in any format
[Apr 10 17:08:01] WARNING[19135][C-00001cf4]: file.c:1017 ast_streamfile: Unable to open vm-newn (format (ulaw)): No such file or directory

Errors are caused by the lack of sound files, for example, in my case in the voice mail one message and when I try to say “you have one (1n.ulaw) new (vm-newn) message, an error occurs and the handset lies down.

Archive with a set of necessary files is enough to simply download from the official site http://downloads.asterisk.org/pub/telephony/sounds/releases/ and unpack to the directory /usr/share/asterisk/sounds
After this, the error should not be.

How to view the configuration of MikroTik

Recently I configured the next MikroTik and I had to share the configuration, so, to see it in the terminal, execute the command:

/export compact

To save the configuration to a file, execute the command:

/export compact file=config

After saving the file will be in the device’s memory, you can see it and download it from the Files menu via the web interface or winbox, ftp, smb, sftp.