Ignoring Bogus Servers in BIND

In the context of BIND (Berkeley Internet Name Domain), the term “Ignore Bogus Server” refers to a security feature that helps prevent the DNS server from accepting responses from servers that are deemed untrustworthy or suspicious. This feature is particularly useful in preventing DNS spoofing and cache poisoning attacks.

Key Concepts

Bogus Server: A DNS server that provides incorrect or misleading information. This could be due to misconfiguration, malicious intent, or server compromise.
DNSSEC (Domain Name System Security Extensions): A suite of extensions that add a layer of security to the DNS protocol by enabling DNS responses to be verified for authenticity.

How it Works

When configured, BIND can be set to ignore responses from servers that are considered “bogus” based on the following criteria:

DNSSEC Validation:

If a DNS server is configured to use DNSSEC, it will only accept responses that can be validated using cryptographic signatures.
If a response cannot be validated (i.e., it fails DNSSEC checks), BIND will treat the response as coming from a bogus server and ignore it.

Configuration Options:

The dnssec-validation option in the BIND configuration file (named.conf) can be set to enable DNSSEC validation.
For example:
plaintext options { dnssec-validation auto; };

Logging and Monitoring:

BIND can be configured to log events related to bogus server detection, which can help administrators monitor potential security issues.

Benefits

Improved Security: By ignoring responses from bogus servers, BIND helps prevent attacks that could compromise the integrity of DNS data.
Reduced Risk of Cache Poisoning: Cache poisoning involves inserting false DNS records into the cache of a DNS resolver. Ignoring bogus responses reduces the risk of this attack.

Conclusion

The “Ignore Bogus Server” feature in BIND enhances the security of DNS operations by ensuring that only trustworthy responses are accepted. This is an important aspect of maintaining DNS integrity, especially in environments where security is a priority.