Port 953DNS RNDC
Port 953 is primarily used by the Remote Name Daemon Control (RNDC), a command utility for controlling the BIND DNS server. It facilitates secure, authenticated communication between administrators and the DNS server, enabling remote management tasks such as reloading zone files and flushing caches. RNDC operates over both TCP and UDP, and by default listens on TCP port 953, providing administrators fine-grained control over DNS server operations..
- transport
- tcp · udp
- in transit
- cleartext
- assignment
- unofficial
- risk
- 2/10
- lookups
- 16,444
2 transports registered
payload readable on path
used by convention
safe
rank 178 of 993 · top 18%
Technical Details
what runs on :953Overview:
Port 953 is reserved by convention for RNDC, a control channel for BIND (Berkeley Internet Name Domain), the most widely used DNS server software. RNDC allows administrators to securely send administrative commands to the named daemon, facilitating seamless remote management.
Protocol Details:
While RNDC primarily utilizes TCP on port 953, it may also employ UDP for certain operations or during initial communication. The connection is typically authenticated and protected via shared secret keys using HMAC-MD5 or newer algorithms, as configured in the rndc.conf and named.conf files. Commands sent through RNDC include reloading zones, refreshing configurations, enabling or disabling query logging, and shutting down the BIND server.
Operational Context:
System administrators rely on RNDC to manage DNS servers without directly accessing the server console, thereby streamlining DNS administration. Because it can control critical DNS functions remotely, ensuring correct configuration of access controls and key management is vital to maintain DNS integrity and availability.
Security Information
exposure of :953risk score
2/ 10safe
routine exposure. this port is rarely the way in on its own — keep it patched and logged and move on.
security averages 3.8 across 216 ports — this one sits 1.8 below.
in transit
cleartext
credentials and payloads are readable by anyone on path
assignment
unofficial
used by convention, not registered — what answers here varies by deployment
reachable over
tcp · udp
udp is connectionless — source addresses are trivially spoofed and it is a reflection favourite
security overview
Common Vulnerabilities:
- Weak Authentication: Using outdated or weak secret keys (e.g., short-length HMAC-MD5) increases susceptibility to brute-force attacks.
- Unauthorized Access: Improper ACL (Access Control List) settings can allow attackers to issue malicious commands, potentially disrupting DNS services.
- Unencrypted Traffic: Older configurations might not enforce encrypted connections, enabling interception or replay attacks.
Common Mitigations:
- Strong Secret Management: Use long, complex shared secrets and modern HMAC algorithms.
- Restrictive ACLs: Limit RNDC access strictly to trusted management IPs via configuration.
- Encrypt Communication: Employ TSIG (Transaction SIGnature) with strong algorithms to authenticate and protect data integrity.
- Regular Auditing: Periodically review and update RNDC configuration, keys, and access controls.
- Network Segmentation: Isolate DNS management interfaces on dedicated administrative networks to reduce exposure.
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the 8 most looked-up other ports in security — 216 ports carry that label.
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|---|---|---|---|---|---|
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| :3268 | Microsoft Global Catalog (GC) | TCPUDP | Security | caution | 54.6k |
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| :3128 | Squid Proxy HTTP | TCP | Web Services | caution | 45.8k |
| :8080 | HTTP Alternate | TCPtls | Web Services | caution | 44.9k |
| :7000 | Vuze HTTPS Tracker | TCPtls | Security | caution | 28.9k |
risk mix of the 8 listed
- caution100%
3 of 8 encrypted