Even today we see a lot of servers that have different services and ports open for rpc and this creates not only potential inward vulnerabilities but perhaps more common, the abuse of your network resources in reflective rpc queries. To stop this problem, you should disable and remove all services relating to rpc or at least block all relevant ports for the service. Surprisingly, there are still some providers and OS installs in Linux that install these services and leave them........

If you get this error, it is often because you have configured Apache with modules that weren't actually installed. Eg. you try to load the PHPmodule but didn't actually install the apache2 php module, so the server can't start. In general, this error can often be caused by issues with problematic modules and/or Apache being configured for modules that have not actually be installed (eg. libapache2-mod-php) is missing. The above results in this less than obv........

mysql reset root password. Oops I can't remember my MySQL root password! [root@centos7test etc]# mysql -u root -p Enter password: ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES) First we need to stop mariadb: systemctl stop mariadb Now we need to restart it with skip-grant-tables whic........

Most of us know the heredoc method but what if you need a basic query done repeatedly and manually while working from bash? It is a pain to manually type mysql and login each time. With this command below you can semi-automate those queries: echo "use somedb; select * from auctions" | mysql -u root --password="yourpassword" Just modify the above to suit your needs and you can add more queries by adding a sem........

By default bind will not respond to outside queries for security reasons. In most distributions you will find the default in /etc/named.conf looks like this at the top under options: listen-on port 53 { 127.0.0.1; }; listen-on-v6 port 53 { ::1; }; directory "/var/named";........

Install Errors on Version 12: This error happened on QEMU emulator version 2.11.1 pve-qemu-kvm_2.11.1-5 on Proxmox/Debian but installing on QEMU.12 on Centos 6 did not produce the error. *Update it is not related to the OS or QEMU version. This happened in Centos 6 too after a second install. What really causes this even though you successfully install........

mytop is one of my favorite tools and it is fairly simple aside from a few caveats and issues that persist to this day. To install it on Centos: yum -y install centos Configure ~/.mytop vi ~/.mytop user=root host=localhost db=test #port=3306 socket=/var/lib/mysql/mysql.sock header=1 color=1 Try runni........

This happened on Centos for no apparent reason with no obvious issue in the logs. Data could be read fine but not written (possibly due to some corruption or out of memory issue in the OpenVZ container is the best guess). All mysql update and insert queries failed freezing without any error log on any database and table. Tried to restart: service mysqld restart Timeout error occurred trying to stop MySQL........

whois in Linux is incredibly out of date and does not seem to recognize most new TLDs domains, but there is a quick and easy tip/hack/tweak for this. An example of new TLD's site as .review .site .club whois somesite.club No whois server is known for this kind of object. bash to the rescue Now I did try to apply this in .bashrc but DONOT! Ithink the * wil........

service named status rndc: connect failed: 127.0.0.1#953: connection refused named (pid 10557) is running... This issue is normally caused by a permissions issue where named doesn't have the permissions to read the rndc.key. Check /var/log/messages: Jan 4 17:06:22 storagebox named[10753]: none:0: open: /etc/rndc.key: permission denied Jan 4 17:06:22 storagebox named[10........

First of all if you're getting this error it is a result of extreme database activity. If you aren't expecting it or it doesn't make sense to you 99% of the time this is a database driven script being exploited (some common examples I see often are things like phpBB being hit by dozens, hundreds or thousands of bots making constant DB write requests). The easiest way to identify this is to restart MySQL and then run the third party tool "mtop" and you'll see all........

Enter the console as root mysql -u root -p Then kill the process (where 1234 = the thread ID) kill 1234 It's also a good idea to use a tool like "mtop" to monitor which processes and queries are slow, killing them is a temporary fix while you try to isolate the actual problem.........

If you have a webserver and find you have high IO/lagginess MySQL is one of the first things to check. It turns out MySQL was my problem and it was creating a high load on my server, especially for IO. How to Enable MySQL Slow Query Logging To Find Slow Performance/Queries vi /etc/my.cnf Add this anywhere under [mysqld] #slow queries log-slow-queries = /var/log/mysql/mysqlslowqueries.log long_query_time = 1........

MySQL SubQueryI was trying to do a sub-query here but it wouldn't work (Syntax Error) in MySQL for some reason even though based on the SQL standards it should be ok. [i:1268bfa39e][b:1268bfa39e]I found the reason this doesn't work. I am using MySQL 3.23 and I read on the MySQL web site that versions before 4.1 DO NOT SUPPORT SUB-QUERIES so it showed me how to rewrite the following as a LEFT join instead of a sub-query. [/b:1268bfa39e][/i:1268bfa39e]........