source: http://www.directadmin.com/forum/showthread.php?s=78bb4e8b8b5deb41fdc7275bb87a051a&threadid=13173&perpage=20&pagenumber=1

http://www.directadmin.com/forum/showthread.php?s=70864a5c335e7705f268e661e0a6d78f&threadid=14285

# ifconfig eth1 192.168.10.12 netmask 255.255.255.0

# cd /etc/sysconfig/network-scripts

Edit the NETMASK lines in the ifcfg-eth0* and in the ifcfg-eth1* files as required.

Set the system wide open file limit:

vi /etc/security/limits.conf

Change/Add the following:

* soft nofile 1024000
* hard nofile 1024000
* soft nproc 10240
* hard nproc 10240

Now do this for /etc/sysctl

vi /etc/sysctl

Add the following

fs.file-max = 1024000

Set the changes

sysctl -w fs.file-max=1024000
sysctl -p
# check changes
cat /proc/sys/fs/file-max

Set the mysqld.service limit (as settings here will override *.cnf ones)

Set both /etc/systemd/system.conf and /etc/systemd/user.conf

vi /etc/systemd/system.conf
vi /etc/systemd/user.conf

Add the following under [Manager] for both:

If you used custombuild to install opcache, then you will need to set the opcache settings there.

cd /usr/local/directadmin/custombuild
 vi options.conf

Change opcache=no to opcache=yes

opcache=yes

Set your opache settings here:

vi custom/opcache/opcache.ini

Here are my settings (This is for a fast server, with 128GB RAM):

Enable DKIM and change the PHP mail SMTP Sender banner

To Change the "Sender" info we have to do the following:

cd /usr/local/directadmin/data/templates/custom/
cp /usr/local/directadmin/data/templates/virtual_host2.conf /usr/local/directadmin/data/templates/custom/
cp /usr/local/directadmin/data/templates/virtual_host2_secure.conf /usr/local/directadmin/data/templates/custom/
sed -i 's/`USER`@`DOMAIN`/no-reply@`DOMAIN`/g' ./virtual_host2*.conf
echo "action=rewrite&value=httpd" >> /usr/local/directadmin/data/task.queue
/usr/local/directadmin/dataskq d

Say you have Pinterest setup on your site to allow pinning or saving of images. However, you obviously don't want this enabled for all images (ex: menu images, footer images, etc).

Here's how to exclude certain images from being recognized by Pinterest:

In Magento, you would add the following to your local.xml, under <reference name="head">:

Install OpenSSL with ALPN support

cd /usr/local/src/
wget ftp://ftp.openssl.org/source/openssl-1.0.2j.tar.gz
tar xzf openssl-1.0.2j.tar.gz
cd openssl-1.0.2j
./config --prefix=/usr/local/lib_http2 no-ssl2 no-ssl3 zlib-dynamic -fPIC
make depend
make install

Install nghttp2 - HTTP/2 Library

cd /usr/local/directadmin/custombuild
./build update
./build nghttp2

​Install HTTP/2 for Apache 2.x

cd /usr/local/directadmin/custombuild
mkdir -p custom/ap2
cp -p configure/ap2/configure.apache custom/ap2/configure.apache
vi custom/ap2/configure.apache

### REPLACE "--with-ssl=/usr" \
### WITH:

        "--enable-http2" \
        "--enable-ssl-staticlib-deps" \
        "--with-ssl=/usr/local/lib_http2" \


### Rebuild apache

./build apache

### Add HTTP/2 settings to httpd-includes.conf

These are some of the basic things I do when I setup a new server

Get the latest directadmin.conf values

With each version of DirectAdmin, new configuration values are introduced that you may not know about. To see ALL these values do the following:

/usr/local/directadmin/directadmin c | sort -n

You can essentially copy/paste the entire results into your /usr/local/directadmin/conf/directadmin.conf replacing anything else in there.

Setup DirectAdmin with an SSL certificate

source: http://help.directadmin.com/item.php?id=15

If you don't own a certificate, you can create your own with letsencrypt.com:

Here's how to redirect ONLY specific domains to HTTPS with .htaccess.

RewriteEngine on

# Redirect all domains to use 'www.'

​RewriteCond %{HTTP_HOST} .
RewriteCond %{HTTP_HOST} !^www\. [NC]
RewriteRule ^ http%{ENV:protossl}://www.%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

# Redirect ONLY specific domains to HTTPS

RewriteCond %{HTTP_HOST} ^(www\.)?(domain1.com|domain2.com|domain3.net)$
RewriteCond %{HTTP:X-Forwarded-Proto} !https [NC]
RewriteCond %{HTTPS} off
RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

What the above does is:

Make sure you have Composer installed.

cd ~
composer global require drupal/console:@stable

There are some new drush Drupal 8 commands that are critical to updating your site. The big new one here, is "drush entitity-updates".  Which should be initiated AFTER "drush updb".

Otherwise, if you check your Drupal 8 "Status Report" you may get an error showing "Entity/field definitions: Mismatched entity and/or field definitions"--which won't be apparent, unless you check the Status Report.

So here goes... 

Clear all cashes (no longer "drush cc all"):

drush cr 

or 

drush cache-rebuild

Update the database (this is still the same, however, you won't be done here):

drush updb

After running "drush updb", you should next run entity updates command:

drush entup

or

There's a bug affecting all magento 1.9 versions, that prevents users from applying multiple coupons to their order--even if "Stop further rules processing" is NOT selected.

Basically, a customer can only apply a single coupon to their order--no stacking of coupons works in Magento 1.9.

Here's the fix, you'll need modman and generate-modman installed:

If you locked yourself out of SSH in WHM/Cpanel for whatever reason--e.g. you specified an invalid AllowUsers in /etc/ssh/sshd_config--you can reload SSH service in safemode, by pasting this into your browser's address bar:

https://YOURSERVER:2087/scripts2/doautofixer?autofix=safesshrestart

Then login with your root credentials, and sshd will be restarted in safemode, allowing you to login and fix your /etc/ssh/sshd_config.

Once done, restart ssh:

service sshd restart

Let's say you want to AUTOMATICALLY delete all "Promotional" emails from your Gmail after 90 days.

Step 1:

Go to Settings -> Filters -> Create a new filter

Step 2:

Type the following into "Has the words" field:

category:promotions older_than:90d

Step 3:

Click "Create filter with this search"

Step 4:

Select "Delete it" and finally click "Create filter" button... 

And... we're done!

The key here is older_than:90d, you can just as easily create whatever time-based filter you want with that.