ModSecurity blocks access to website in Plesk and not sure how to fix it? Find out what our experts suggest.

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Let’s take a look at how our Support Team is ready to help customers resolve the error: SERVFAIL looking up A for example.com.

How to resolve: ModSecurity blocks access to website in Plesk

ModSecurity, also known as Modsec is a WAF( web-based firewall) application. It is popular all over the globe, given its several useful features. Unfortunately, it may throw up an issue every now and then. ModSecurity tends to block access to a website when the content of the directory looks like this:

# ls -la /var/cache/modsecurity/
drwxr-x--- 2 root root 4096 May 4 15:12 .
drwx------ 10 root root 4096 Apr 15 10:52 ...

However, the error may exist if the entire directory is missing, resulting in the following message:

# ls -la /var/cache/modsecurity/
ls: cannot access /var/cache/modsecurity/: No such file or directory

Additionally, this specific error also causes the following message to occur in the /var/log/modsecurity_audit.log file while blocking access to the website:

Message: collections_remove_stale: Failed to access DBM file “/var/cache/modsecurity/apache-global”: Permission denied Message: collections_remove_stale: Failed to access DBM file “/var/cache/modsecurity/apache-ip”: Permission denied

This handy solution by our Support Team will put things right in no time at all:

1. First, let’s log in to the server via SSH.
2. After that, we have to re-create the missing directory in addition to setting up the proper permissions and ownership:

   # mkdir /var/cache/modsecurity/
   
   # chmod 750 /var/cache/modsecurity/
   
   # chown apache:root /var/cache/modsecurity/
3. Then, it is time to fix permissions and re-create files with the following commands:

   # chown apache:root /var/cache/modsecurity/./
   
   # chmod 755 /var/cache/modsecurity/../
   
   # cd /var/cache/modsecurity/
   
   # touch apache-global.dir && chown apache:apache apache-global.dir && chmod 640 apache-global.dir
   
   # touch apache-global.pag && chown apache:apache apache-global.pag && chmod 640 apache-global.pag
   
   # touch apache-ip.dir && chown apache:apache apache-ip.dir && chmod 640 apache-ip.dir
   
   # touch apache-ip.pag && chown apache:apache apache-ip.pag && chmod 640 apache-ip.pag
4. If SELinux is in use, our Support Techs recommends executing the following command as well:

   # chcon -R -t httpd_cache_t /var/cache/modsecurity

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Conclusion

To sum up, our skilled Support Engineers at Bobcares demonstrated how to proceed when ModSecurity blocks access to website in Plesk.