If my PC was left connected to Cloudflare WARP, I would not be able to remote access it via Splashtop from an external location. Also Dropbox is blocked when connected. The way I solved this is to add Split Tunnels in the Cloudflare backend to bypass domains used by Dropbox and Splashtop.
*.dropbox.com *.dropboxusercontent.com *.dropboxapi.com *.dropboxstatic.com *.api.splashtop.com *.relay.splashtop.com
Today I wanted to solve the issue of caching on the email signature banners once and for all. I don’t want any browsers or email clients to cache the image, so I started searching for solutions.
The best one I could find was this one:
<Files {FILENAME}>
FileETag None
Header unset ETag
Header set Cache-Control "max-age=0, no-cache, no-store, must-revalidate"
Header set Pragma "no-cache"
Header set Expires "Wed, 11 Jan 1984 05:00:00 GMT"
</Files>
So specifically to stop caching on the email signature file, I created an .htaccess file containing this:
<Files emailsignature.gif> FileETag None Header unset ETag Header set Cache-Control "max-age=0, no-cache, no-store, must-revalidate" Header set Pragma "no-cache" Header set Expires "Wed, 11 Jan 1984 05:00:00 GMT" </Files>
And saved the file here:
windeurope.org/wp-content/uploads/images/banners/.htaccess
By default, Redhat-based linux has a user group called the “wheel” group. Members of the wheel group are automatically granted sudo privileges. Adding a user to this group is a quick and easy way to grant sudo privileges to a user.
Your CentOS 7 installation may or may not have the wheel group enabled.
Open the configuration file by entering the command:
visudo
Scroll through the configuration file until you see the following entry:
## Allows people in group wheel to run all commands # %wheel ALL=(ALL) ALL
If the second line begins with the # sign, it has been disabled and marked as a comment. Just delete the # sign at the beginning of the second line so it looks like the following:
%wheel ALL=(ALL) ALL
Then save the file and exit the editor.
To add a user to the wheel group, use the command:
usermod -aG wheel NewUser
As usual, replace NewUser with the name of the user receiving sudo privileges.
If there’s a problem with the wheel group, or administrative policy prevents you from creating or modifying groups, you can add a user directly to the sudoers configuration file to grant sudo privileges.
In the terminal, run the following command:
visudo
This will open the /etc/sudoers file in a text editor.
Scroll down to find the following section:
## Allow root to run any commands anywhere root ALL=(ALL) ALL
Right after this entry, add the following text:
NewUser ALL=(ALL) ALL
Replace NewUser with the username you created in Step 2. This section should look like the following:
## Allow root to run any commands anywhere root ALL=(ALL) ALL NewUser ALL=(ALL) ALL
Save the file and exit.
Some plugins create tables in MYSQL without primary keys which may break exporting and importing actions.
We can identify where exactly with this SQL script:
SELECT
t.TABLE_NAME
FROM INFORMATION_SCHEMA.TABLES AS t
LEFT JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE AS k
ON (
t.TABLE_NAME = k.TABLE_NAME
AND k.CONSTRAINT_SCHEMA = t.TABLE_SCHEMA
AND k.constraint_name = 'PRIMARY'
)
WHERE
t.TABLE_SCHEMA NOT IN ('information_schema', 'performance_schema', 'mysql', 'sys')
AND t.TABLE_SCHEMA = 'database name' -- put database name here
AND k.constraint_name IS NULL;
If you have a big Twitter account and you want to completely delete all your old tweets in one go, here is how to do it:
Tutorial: How to delete all your Tweets for free (code and userscript in comments)
byu/lucahammer inTwitter
On some of our servers, the /boot partition get’s 100% full and then things like yum updates stop working.
Instead of attempting a dangerous and complicated manoeuvre to resize the (boot!) partition we can just take the following steps to stop the /boot partition from filling up in the first place:
Delete all old kernel versions
# dnf remove --oldinstallonly
Then edit the yum conf:
# vi /etc/yum.conf
Update the install limit to 2:
[main] gpgcheck=1 installonly_limit=2 clean_requirements_on_remove=True best=True skip_if_unavailable=False
Sometimes your provider changes your IP address and if you have IP Access Control turned on, you will not be able to access Webmin anymore. And of course you won’t be able to update your IP address in Webmin if you can’t access it anymore.
So in that case you need to use SSH and edit this config file:
# vi /etc/webmin/miniserv.conf
Look for the line “allow” and edit the IP address(es) as needed:
error_handler_404=404.cgi error_handler_403=403.cgi error_handler_401=401.cgi allow=151.248.55.185 77.109.118.242 80.211.197.221 alwaysresolve=0 libwrap= trust_real_ip=0
Doing a yum update, I received this error and the update quit:
Errors during downloading metadata for repository 'appstream': - Curl error (6): Couldn't resolve host name for http://mirrorlist.centos.org/?release=8-stream&arch=x86_64&repo=AppStream&infra=stock [Could not resolve host: mirrorlist.centos.org] Error: Failed to download metadata for repo 'appstream': Cannot prepare internal mirrorlist: Curl error (6): Couldn't resolve host name for http://mirrorlist.centos.org/?release=8-stream&arch=x86_64&repo=AppStream&infra=stock [Could not resolve host: mirrorlist.centos.org]
Because CentOS 8 reached end-of-life, the yum repositories at “mirrorlist.centos.org” stopped working and need to be updated to new CentOS 8 Stream repos.
You can batch edit all the files in /etc/yum.repos.d/ with these commands:
sed -i s/mirror.centos.org/vault.centos.org/g /etc/yum.repos.d/*.repo sed -i s/^#.*baseurl=http/baseurl=http/g /etc/yum.repos.d/*.repo sed -i s/^mirrorlist=http/#mirrorlist=http/g /etc/yum.repos.d/*.repo
The content of the repo files will change like this:
[baseos] name=CentOS Stream $releasever - BaseOS #mirrorlist=http://mirrorlist.centos.org/?release=$stream&arch=$basearch&repo=BaseOS&infra=$infra baseurl=http://vault.centos.org/$contentdir/$stream/BaseOS/$basearch/os/ gpgcheck=1 enabled=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial
Some hosting providers (like DigitalOcean’s DBaaS) are very strict about importing a database which contains missing primary keys.
So to locate where those tables are, we can run the following query:
SELECT
t.TABLE_NAME
FROM INFORMATION_SCHEMA.TABLES AS t
LEFT JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE AS k
ON (
t.TABLE_NAME = k.TABLE_NAME
AND k.CONSTRAINT_SCHEMA = t.TABLE_SCHEMA
AND k.constraint_name = 'PRIMARY'
)
WHERE
t.TABLE_SCHEMA NOT IN ('information_schema', 'performance_schema', 'mysql', 'sys')
AND k.constraint_name IS NULL;
From here:
https://moiseevigor.github.io/programming/2015/02/17/find-all-tables-without-primary-key-in-mysql/
The Gandi servers suck so bad that when you reboot them, sometimes they don’t come back online. If this happens, you need to do this:
GRUB > prompt, enter:
configfile (xen/xvda1)/boot/grub2/grub.conf
e” to continue with editing.16 from linux16 and initrd16
linux16/boot/................ initrd16/boot/................