Protocol-Specific Security Rules

1 min read Web Security Fundamentals

Protocol-Specific Security Rules

Different protocols require specific security considerations beyond simple port filtering. Understanding protocol behaviors enables creation of more sophisticated rules that block malformed or malicious traffic while allowing legitimate communications.

For HTTP/HTTPS, implement protocol validation:

Allow HTTP from any to web_server_ip where method in (GET,POST,PUT,DELETE,HEAD,OPTIONS)
Deny HTTP from any to web_server_ip where header_length > 8192
Deny HTTP from any to web_server_ip where url_length > 2048

WebSocket connections require special handling:

Allow TCP from any to web_server_ip port 443 where 
    http_header contains "Upgrade: websocket" and
    established_connection exists

Block obsolete and dangerous protocols:

Deny all from any to web_server_ip protocol in (telnet,ftp,tftp,snmp)