DNS Logging and Monitoring
Bit the Chipmunk, AWS Expert published on
Hey there, network adventurers! Bit the Chipmunk here — your furry study buddy, ready to dig into some DNS dirt!
In this article, we’ll explore how to design DNS solutions that meet public, private, and hybrid requirements — and most importantly, how to log and monitor them like a pro.
This topic pops up often on the AWS Advanced Networking Specialty Exam, so let’s make sure you can sniff out every DNS clue that appears in a scenario question. 🕵️♂️
🌎 1. Public, Private, and Hybrid DNS — Quick Refresher
Before diving into logs, let’s make sure we’re on the same page:
| Type | Managed By | Use Case | Example Service |
|---|---|---|---|
| Public DNS | AWS Route 53 Public Hosted Zone | Exposes domains to the internet | example.com |
| Private DNS | Route 53 Private Hosted Zone | Internal resolution inside a VPC | corp.local |
| Hybrid DNS | Route 53 Resolver + rules | Mix of on-premises and cloud resolution | Connect on-prem DNS to VPC DNS |
You’ll often see exam questions where a company has both on-premises DNS servers and VPC DNS — and the solution must ensure visibility and auditability of all queries.
That’s where logging and monitoring come in!
🔍 2. DNS Logging and Monitoring Options on AWS
Here are the key AWS tools you need to know, and when to use them:
🧠 a. Route 53 Resolver Query Logging
(Private DNS Logging — Exam Favorite!)
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Captures DNS queries made within VPCs using the Amazon Route 53 Resolver.
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You can log:
- Queries from EC2 instances in your VPC
- Queries forwarded to on-prem DNS
- Responses from Route 53 Private Hosted Zones
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Logs can be sent to:
- Amazon CloudWatch Logs
- Amazon S3
- Amazon Kinesis Data Firehose
Why it matters for the exam:
Resolver Query Logging is the only native way to monitor and audit private DNS activity inside AWS.
Typical exam scenario:
“A security team must analyze which internal hosts are querying malicious domains. Which feature helps?” ✅ Answer: Route 53 Resolver Query Logging.
🌐 b. Route 53 Public DNS Query Logging
- For public hosted zones, Route 53 can log DNS query data.
- You can see which domains are being queried, the query type, and source IPs.
- Logs go to CloudWatch Logs.
Exam tip: Used mainly for DNS analytics, troubleshooting, and DDoS detection for public-facing domains.
🧭 c. VPC Flow Logs (Supplemental Logging)
- Logs all network flows, including traffic to the VPC DNS resolver (169.254.169.253).
- While not DNS-specific, they help identify which instances are sending DNS requests.
Exam angle:
Used for network-level visibility, not DNS query content. You might see this in combination with Route 53 logs in a security monitoring question.
☁️ d. CloudTrail for Configuration Auditing
- Records who made changes to Route 53 hosted zones or Resolver settings.
- Doesn’t show query traffic — just configuration events like “created hosted zone” or “updated rule.”
Exam tip: If the question asks for auditing administrative changes, CloudTrail is your answer — not Resolver Query Logs.
🧰 e. AWS Security Services Integration
You might see these in multi-service scenarios:
| Service | Integration | What It Adds |
|---|---|---|
| GuardDuty | Uses DNS logs to detect suspicious domain lookups | Security threat detection |
| Security Hub | Aggregates GuardDuty and Route 53 findings | Centralized visibility |
| CloudWatch Logs Insights | Query Route 53 Resolver logs | Investigate DNS behavior |
Exam pattern:
“The security team must detect exfiltration attempts via DNS tunneling.” ✅ Answer: Enable Route 53 Resolver Query Logging + GuardDuty.
🧩 3. Designing for Hybrid DNS Visibility
When a company has both on-prem DNS and AWS DNS, visibility often gets tricky.
Solution pattern:
On-prem DNS ↔ Route 53 Resolver Inbound/Outbound Endpoints
- Enable Resolver Query Logging
That combo lets you:
- Forward DNS queries between environments
- Log every lookup across hybrid networks
- Store logs centrally in S3 or CloudWatch for analysis
Exam tip: If the question mentions “hybrid” or “on-prem integration,” look for Route 53 Resolver endpoints + query logging.
🧠 Bit’s Exam Nutshell
| Goal | Service | Where Logs Go | Exam Keyword |
|---|---|---|---|
| Log private DNS queries | Route 53 Resolver Query Logging | CloudWatch / S3 / Firehose | “Internal DNS visibility” |
| Log public DNS queries | Route 53 Public DNS Query Logging | CloudWatch Logs | “Public domain monitoring” |
| Track configuration changes | CloudTrail | CloudTrail logs | “Auditing admin changes” |
| Analyze DNS security threats | GuardDuty + Resolver Logs | Security Hub / CloudWatch | “Detect DNS tunneling or malicious domains” |
| Hybrid DNS visibility | Resolver Endpoints + Query Logging | Centralized storage | “Hybrid DNS monitoring” |
🎯 Bit’s Final Tips
- 💡 Remember: Route 53 has two kinds of logs — public and private (Resolver).
- 🧩 CloudTrail ≠ Query logs — it’s for config auditing only.
- ⚡ GuardDuty analyzes DNS logs automatically for security threats.
- 🧠 Hybrid DNS = Resolver endpoints + Query Logging.
If you can recognize which logging service fits the scenario, you’ll ace every DNS logging question the exam throws at you!
Now scamper off and practice, little network squirrel — you’re one step closer to that certification acorn! 🌰✨