Do not disclose private IP addresses and routing information to unauthorized parties

Security scan tools try to exploit known vulnerabilities in your web applications. This helps system administrators and software developers to detect potential issues in advance and take an action before the applications go live.

One of the vulnerabilities security scan tools look for (and attackers try to exploit) is the vulnerability specified in PCI DSS 3.2 requirement 1.3.7:

Do not disclose private IP addresses and routing information to unauthorized parties