Jan 082010
 

Hi,

When I started this blog, I started it for my own benefit so I could remember those little tweaks or fixes which escape memory at crucial times when a needed repair or a new issue arose that I had never dealt with before. When I would research these issues, I would come across great posts and information I wanted to remember and posted that information here. If I did not give credit where credit was due regarding those posts and if you find something that was posted by you, please let me know and I will credit the post to you. I cannot remember where I pulled all of the information from so, if you see something that is yours, do not fret, I am not stealing your shtuff, I am posting it so all can read and learn from the mistakes and information I have gathered. Most of the posts are mine, but not all. Thank you all for your patience and information you have shared to better improve the linux experience.

Oh and by the way, if you see a post that has outdated or incorrect information, please, please, pretty please let me know so I can update it. Believe it or not, I use this site also and I want my information to be up to date as well. Thanks again for visiting.

Share This!
 Posted by at 7:57 pm
Oct 312016
 

Hi!

Do you have a client who says that they cannot access their sites/server and insists it’s a network issue, but their IP addresses does not seem to be blocked by csf.deny and their sites are not loading in several parts of the world with a site checker like https://www.site24x7.com/check-website-availability.html or others?

Well do I have quite the solution for you!

This morning, we verified an issue regarding a CSF/Spamhaus update in which CSF blocks any IP address that is over 128.0.0.0. This is due to a subnet that does not exist in the official list, 172.103.64.0/1:

https://www.spamhaus.org/drop/drop.lasso

Unfortunately, CSF will round the 172.103.64.0/1 down to 128.0.0.0/1 which will block all IP addresses above that range. To remedy this, after verifying the subnet issue is present, remove the SPAMDROP list file:

rm /var/lib/csf/csf.block.SPAMDROP

And restart CSF

csf -r

Restarting CSF will generate a new (and correct) SPAMDROP list without the wonky subnet.

Now, verify the sites on the server can load now throughout the world without issue:

https://www.site24x7.com/check-website-availability.html

Enjoy!!!

Share This!
Sep 182016
 
Hi all,

 

I have been noticing quite a few issues relating to the cPanel p0f service crashing and sending e-mail notices to customers. This appears to be related to a recent cPanel update based on early reports. Fortunately, the fix is quite simple and should only require you to run the following commands:
/scripts/check_cpanel_rpms --fix
/scripts/restartsrv_p0f

What is the PoF service you ask? Well cpanel says this is the Passive OS Fingerprinting Daemon

If you are on a CentOS7 server, you also need to create an extra entry to the yum.conf excludes, I have checked and confirmed that this fix does work and should be a permanent solution.

Edit:

/etc/yum.conf, add p0f*

to the exclude line. You can add it to the end if you want. It will automatically sort it in alphabetical order.
Change:

exclude=courier* dovecot* exim* filesystem httpd* mod_ssl* mydns* mysql* nsd* php* proftpd* pure-ftpd* spamassassin* squirrelmail*

to

exclude=courier* dovecot* exim* filesystem httpd* mod_ssl* mydns* mysql* nsd* p0f* php* proftpd* pure-ftpd* spamassassin* squirrelmail*

and then you can run /scripts/upcp and /scripts/check_cpanel_rpms without triggering the issue again. Otherwise at the next upcp the issue will reoccur again and send out more emails about being broken.

cPanel’s official fix to this is slightly different. They state:  “The issue happens when the EPEL yum repo is enabled. A yum update installs the p0f package from EPEL instead of the cPanel provided p0f package. To correct this, you should added p0f*.el7.* to the excludes line in /etc/yum.conf, and ran /scripts/check_cpanel_rpms –fix to get the cPanel provided p0f package installed. Then you shouldn’t have this issue again.

So please add “p0f*.el7.*” to the excludes line instead of just “p0f*” as this will prevent this from ever updating at all, while the former entry “p0f*” should only prevent it from updating from non-cPanel sources.

Share This!
Aug 162016
 
I recently found a specific explanation for why I keep seeing mysql settings being off in my.cnf and causing load issues.
Recent changes in WHM have added an option to Tweak settings that will allow WHM to determine the “best” settings value. So anytime mysql is restarted from within cpanel, the settings are changed/modified. These settings are on by default.
  • Allow cPanel & WHM to determine the best value for your MySQL open_files_limit configuration?
    This setting’s value defaults to On.
  • Allow cPanel & WHM to determine the best value for your MySQL max_allowed_packet configuration?
    This setting’s value defaults to On.
  • Allow cPanel & WHM to determine the best value for your MySQL innodb_buffer_pool_size configuration?
    This setting’s value defaults to On.
If you are experiencing load issues of unknown origin, this would be something else to check.
Documentation can be found at the below link and is current as of Jun 24, 2016
Share This!
Aug 112016
 

https://www.gofundme.com/2j8nnw4

I normally would not do this here but a friend of mine is in a bad spot, working two job, going to school and needs help. Please check it out and drop a $1.00, $2.00, $5.00 or whatever you can to help. She’s a single mom with two small kids who could use a hand and I know this killed her to ask for this… she does not know I am dropping this here…

I’ve been here long enough to know how generous, kind and awesome my fellow g33k’s are in helping those who have hit a rough spot in life…

Thanks for anything you can do to help in advance…

(p.s. she’s an awesome mom and deserves a break!)

https://www.gofundme.com/2j8nnw4

Share This!
Jun 172016
 

The Problem:

There is an issue on CloudLinux 6.8 and CentOS 6.8 servers with the nss package version numbered 3.21.0-8. In general, if you see either:

curl https://google.com > /dev/null
Illegal instruction (core dumped)

or

rhn_check
Illegal instruction (core dumped)

In both cases, the fix that is being advised amounts to downgrading the nss packages to version 3.21.0-0.3.
The instructions are different between CloudLinux and CentOS.
 

CloudLinux

The older package is still in CloudLinux’s repositories, so this is easy. Run the following command and check that you are going to 3.21.0-0.3

NSS_DISABLE_HW_GCM=1 yum downgrade nss nss-util nss-tools nss-sysinit

Then edit the

vim /etc/yum.conf

file adding nss* to the end of the exclude= line like so

exclude=courier* dovecot* exim* filesystem httpd* mod_ssl* mydns* mysql* nsd* php* proftpd* pure-ftpd* spamassassin* squirrelmail* nss*

Then, check your work with the following command

curl https://google.com > /dev/null

 

CentOS

CentOS is a bit more difficult, since everything just upgraded to CentOS 6.8 and the older package is not in the system repositories.

Create the file

touch /etc/yum.repos.d/nss-fix.repo

with the following contents:

[nss-fix]
name=repository used solely to fix nss
baseurl=http://vault.centos.org/6.7/updates/x86_64/
enabled=0
includepkgs=nss*
#gpgcheck=1
priority=3

Then, run the following command and check that you are going to 3.21.0-0.3

yum --enablerepo=nss-fix downgrade nss nss-sysinit nss-util nss-tools

Next, change

vim /etc/yum.conf

adding nss* to the end of the exclude= line like so

exclude=courier* dovecot* exim* filesystem httpd* mod_ssl* mydns* mysql* nsd* php* proftpd* pure-ftpd* spamassassin* squirrelmail* nss*

Check your work with the following command

curl https://google.com > /dev/null
Share This!