There are 50 posts filed in Linux ( this is page 9 of 10).
You can see this error when adding new Users in PhpMyAdmin. To fix this you can try to run following command from bash:
mysql_upgrade --force -u root -p
and enter mysql root password.
If you still get the same error, you are running old version of phpmyadmin and you need to update it – https://www.phpmyadmin.net/
Simple one liner:
cat access.log | awk '{print $1}' | sort -n | uniq -c | sort -nr | head -20
And if needed, you can block some IP addresses in ufw firewall like this
root@vmware:/# ufw insert 1 deny from 12.12.12.12 Rule inserted
Every computer connect to internet should have firewall (Uncomplicated Firewall). Luckily there’s a super easy one in Ubuntu that can be set up in just few clicks.
First check the status
root@vmware:/# ufw status Status: inactive
Firewall is disabled at the moment.
First make sure you enable services that you know you’ll be using – in most cases this will be SSH and Apache.
root@vmware:/# ufw allow 'Apache Full' Rules updated Rules updated (v6) root@vmware:/# ufw allow 'OpenSSH' Rules updated Rules updated (v6)
Now that you have enabled SSH you can also enable the firewall.
root@vmware:/# ufw enable Command may disrupt existing ssh connections. Proceed with operation (y|n)? y Firewall is active and enabled on system startup
You can easily view list of active rules like this
root@vmware:/# ufw status numbered
Status: active
To Action From
-- ------ ----
[ 1] Apache Full ALLOW IN Anywhere
[ 2] OpenSSH ALLOW IN Anywhere
[ 3] Apache Full (v6) ALLOW IN Anywhere (v6)
In many cases you won’t use the default SSH port, but rather something like 2020, in that case, you need to do this
root@vmware:/# ufw allow 2020/tcp Rule added Rule added (v6)
If you want to block an IP address, you need to make sure to place this rule at very top of the list. UFW looks through the list and it stops after it finds first match. That means adding an IP at the bottom of the list won’t prevent it from accessing Apache port.
Here is the right way to do it
root@vmware:/# ufw insert 1 deny from 12.12.12.12 Rule inserted root@vmware:/# ufw status Status: active To Action From -- ------ ---- Anywhere DENY 12.12.12.12 Apache Full ALLOW Anywhere OpenSSH ALLOW Anywhere
Now you can be 100% sure that 12.12.12.12 can’t access port on your Ubuntu.
You need to do a numbered list first.
root@vmware:/# ufw status numbered
Status: active
To Action From
-- ------ ----
[ 1] Anywhere DENY IN 12.12.12.12
[ 2] Apache Full ALLOW IN Anywhere
[ 3] OpenSSH ALLOW IN Anywhere
[ 4] 2020/tcp ALLOW IN Anywhere
[ 5] 2020/tcp (v6) ALLOW IN Anywhere (v6)
Lets say you want to remove the 3th rule, access to OpenSSH ( port 22 ), then you do
root@vmware:/# ufw delete 3
root@vmware:/# ufw allow 3306/tcp Rule added Rule added (v6)
If you have made a local commit and want to get out of it, just do:
git pull --rebase
If you are setting up nginx,chances are you will discover your worker_connections is at some low number, such as 1024.
You can’t increase this number unless you increase kernel limit as well.
First of all run cat /proc/sys/fs/file-max to discover your maximum limit.
abc@ubuntu:~$ cat /proc/sys/fs/file-max 1048576 abc@ubuntu:~$ ulimit -n 1024
As you can see there’s plenty of space for improvement. Lets say I want my new ‘ulimit -n’ to read 131072.
abc@ubuntu:~$ sudo nano /etc/sysctl.conf
add
fs.file-max = 131072
run
sudo sysctl -p
edit
sudo nano /etc/security/limits.conf
add
* soft nproc 131072 * hard nproc 131072 * soft nofile 131072 * hard nofile 131072 root soft nproc 131072 root hard nproc 131072 root soft nofile 131072 root hard nofile 131072
sudo nano /etc/pam.d/common-session
add
session required pam_limits.so
And that’s it. Log out and in and try ulimit -n
abc@ubuntu:~$ ulimit -n 131072
Now you can edit nginx as well
events {
worker_connections 131072;
use epoll;
multi_accept on;
}