When working in a network environment where you don't have administrative access to all machines, identifying the DNS server software running on a remote host can be valuable for security assessments, compatibility checks, or troubleshooting purposes. Here are several technical approaches to accomplish this.

The simplest method is using the dig command with CHAOS class queries:

dig @192.168.1.100 version.bind CHAOS TXT
dig @192.168.1.100 hostname.bind CHAOS TXT
dig @192.168.1.100 authors.bind CHAOS TXT

Many DNS servers (like BIND) will respond with version information when queried this way.

NMAP offers several scripts specifically designed for DNS service detection:

nmap -sU -p 53 --script dns-nsid 192.168.1.100
nmap -sU -p 53 --script dns-service-discovery 192.168.1.100
nmap -sU -p 53 --script dns-version 192.168.1.100

The -sU flag is crucial as DNS primarily uses UDP protocol.

Different DNS implementations have distinct behavioral patterns:

• BIND: Supports EDNS0 and DNSSEC extensions
• Windows DNS: Often leaks internal domain information
• dnsmasq: Returns minimal responses and typically runs on port 53 of gateways

Capture DNS traffic and examine:

1. EDNS options in response packets
2. TCP fallback behavior
3. Response delay patterns
4. Supported DNS query types

Some servers respond to special queries:

# PowerDNS
dig @192.168.1.100 pdns-control

# Microsoft DNS
nslookup -type=all -q=nodead 192.168.1.100

Remember that:

• Some organizations consider DNS reconnaissance as suspicious activity
• Version information may be intentionally hidden
• Rate limit your queries to avoid triggering security systems

Consider using specialized tools like:

• Fierce (DNS reconnaissance tool)
• DNSRecon
• dnstracer

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When working in a network environment, you might encounter situations where you need to identify the DNS server software running on a remote host. This could be for compatibility testing, security auditing, or troubleshooting purposes. Here's how you can approach this problem systematically.

The simplest method is to query the DNS server's version information directly. Many DNS servers respond to version.bind queries in the CHAOS class:

dig +short chaos txt version.bind @dns-server-ip

For example, if the server is running BIND, you might get a response like:

"9.16.1-Ubuntu"

Nmap includes scripts specifically designed for DNS server detection:

nmap -sU -p 53 --script dns-nsid,dns-update,dns-version @dns-server-ip

This command will:

• Use UDP scanning (-sU) on port 53
• Run three DNS-related scripts
• Attempt to identify the server software and version

Different DNS servers have unique response patterns you can analyze:

dig +norecurse +noauthority +noadditional +nostats +noquestion @dns-server-ip example.com ANY

Pay attention to:

• Response headers and flags
• EDNS support and implementation
• Error message formats

Some DNS servers implement proprietary features that can reveal their identity:

# Check for PowerDNS specific features
dig +short chaos txt auth.version.bind @dns-server-ip

# Microsoft DNS server check
nslookup -q=txt -class=chaos version.bind dns-server-ip

When probing DNS servers:

• Respect network policies and obtain proper authorization
• Limit query rates to avoid being blocked
• Be aware that some servers might log these queries

Here's a simple Python script to automate version detection:

import dns.resolver

def detect_dns_version(server_ip):
    try:
        resolver = dns.resolver.Resolver()
        resolver.nameservers = [server_ip]
        answer = resolver.resolve("version.bind", "TXT", "CH")
        for rdata in answer:
            return str(rdata)
    except Exception as e:
        return f"Detection failed: {str(e)}"

print(detect_dns_version("192.168.1.1"))