Unauthorized HTTP Method Usage: Logs showing unauthorized methods being attempted on the server, like TRACE or PATCH.

The IP attempted to register with the VOIP server using an invalid username.

This IP gave off a red flag for hosting a hidden command and control server for malicious bots.

The IP attempted to send emails from the Postfix server without proper authentication.

The IP attempted to login to the Postfix server with an invalid username.

It made multiple attempts to initiate malicious File Transfer Protocol (FTP) sessions with the Postfix service.

The IP attempted to use the Mail server to relay emails with misleading headers to other servers.

It showed unusual activity in the server's error logs.

Multiple requests with the same Via header.

This IP was reported for attempting to register a large number of SIP extensions in a short time, a sign of a potential brute force attack.

The IP attempted to use the Mail server to relay phishing emails to other servers.

This IP made wrongful manipulations indicating the operation of malicious downgrader.

This IP belongs to Home Depot.

This malicious IP was reported for attempting to perform a FTP Format String attack, exploiting format string vulnerabilities to crash the FTP server or execute arbitrary code.

A series of active scareware campaigns was traced back to this IP address.

The IP was actively engaged in spear-phishing attacks, aimed at high-ranking officials within our network.

It attempted to exploit known vulnerabilities in the Postfix software.

This IP belongs to Cisco Systems.

This IP directed malicious network traffic to our servers with the intent to crash them.

This IP belongs to Valero Energy.

This IP belongs to Deere.

This IP belongs to Fannie Mae.

The IP attempted to register with the VOIP server using an invalid username.

Too Many HTTP GET Requests: An unusually high number of HTTP GET requests from a single IP or a small set of IPs could indicate a DoS attack.

This IP was responsible for circulating malicious images masked with spyware.