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Security

Hardening, firewalls, malware, and DDoS protection.

23 articles Updated regularly

Beginner guides

2 guides

Intermediate guides

11 guides

Understanding DDoS protection at UnderHost

How UnderHost mitigates DDoS attacks, what protection is included by location, how attacks affect yo...

Intermediate 8 min Security DDoS June 2026

Linux file permissions explained for web hosting

Understand what file permissions mean (rwx, 644, 755), how to read and set them in cPanel and via co...

Intermediate 7 min Security Files June 2026

How to recover from a hacked website

Step-by-step guide to recovering from a website hack or compromise: contain the damage, identify the...

Intermediate 10 min Security Malware June 2026

How to secure your website

Practical website hardening: enable SSL, use a web application firewall, set strong passwords, keep ...

Intermediate 11 min Security SSL June 2026

CSR generation-create certificate signing request

Generate CSR (Certificate Signing Request) for SSL certificates. Submit to CA for certificate approv...

Intermediate 10 min Security SSL June 2026

CSR validation-verify certificate request details

Validate CSR before submission to Certificate Authority. Check domain, organization, and cryptograph...

Intermediate 10 min Security Validation June 2026

Email encryption with TLS-secure SMTP, POP3, IMAP

Enable TLS encryption for email servers (SMTP, IMAP, POP3) to protect messages in transit....

Intermediate 9 min Security Email June 2026

Security HTTP headers-prevent attacks and protect browsers

Configure Content-Security-Policy, X-Frame-Options, HSTS, X-Content-Type-Options, and other security...

Intermediate 11 min Security HTTP Headers June 2026

TLS versions-use TLS 1.2 or 1.3 for security

Disable outdated SSL 3.0, TLS 1.0, 1.1. Use TLS 1.2 (minimum) or TLS 1.3 (recommended) for strong en...

Intermediate 10 min Security TLS\/SSL June 2026

Wildcard SSL certificates-secure unlimited subdomains

Wildcard certificates (*.domain.com) secure unlimited subdomains with one certificate. Cheaper than ...

Intermediate 9 min Security Wildcard June 2026

SSH hardening: Secure your server with key practices | UnderHost

Harden SSH security on your VPS or dedicated server. Disable root login, use SSH keys, change defaul...

Intermediate 12 min SSH Security June 2026

Advanced guides

10 guides

Malware cleanup-how to remove malicious files from your hosting account

Step-by-step guide to finding and removing malware from a shared hosting account. Covers scanning to...

Advanced 10 min Security Malware June 2026

ACME DNS validation for Let's Encrypt SSL certificates

Use DNS validation to issue SSL certificates via ACME. How DNS-01 challenge works, wildcard certs, D...

Advanced 11 min SSL DNS June 2026

Certificate pinning-prevent man-in-middle attacks

Pin SSL certificates to prevent attackers from intercepting traffic with different certificates....

Advanced 9 min Security Pinning June 2026

Code signing certificates-sign software and scripts securely

Sign executable files, plugins, and scripts with code signing certificates. Verify authenticity and ...

Advanced 10 min Security Code June 2026

DNSSEC-secure DNS against spoofing attacks

Enable DNSSEC to prevent DNS spoofing and cache poisoning. Cryptographically sign DNS records....

Advanced 10 min Security DNS June 2026

ECC SSL certificates-elliptic curve modern encryption

ECC certificates offer stronger encryption with smaller key sizes than RSA. Support ECDSA signing....

Advanced 9 min Security ECC June 2026

Fail2Ban intrusion prevention-block brute force attacks

Fail2Ban blocks IP addresses after repeated failed login attempts. Configure for SSH, FTP, and WordP...

Advanced 10 min Security Brute Force June 2026

iptables firewall configuration-basic rules for servers

Configure Linux firewall with iptables. Allow SSH, HTTP/HTTPS, block unnecessary ports, and persist ...

Advanced 11 min Security Firewall June 2026

Server firewall rules-allow and block traffic by port and IP

Configure firewall rules on VPS servers with UFW or iptables. Allow SSH, HTTP, HTTPS, and block mali...

Advanced 10 min Security Firewall June 2026

SSL key management-protect private keys

Secure SSL private keys, backup safely, rotate periodically, and use HSM for high-security environme...

Advanced 10 min Security Keys June 2026

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