From 45bc59ac446f9de42f6af2dd12db9dcb1d3cf469 Mon Sep 17 00:00:00 2001 From: medusa Date: Sun, 20 Jul 2025 20:59:00 -0500 Subject: [PATCH] Update tech_docs/cloud/aws_notes.md --- tech_docs/cloud/aws_notes.md | 122 ++++++++++++++++++++++++++++++++++- 1 file changed, 121 insertions(+), 1 deletion(-) diff --git a/tech_docs/cloud/aws_notes.md b/tech_docs/cloud/aws_notes.md index 0be4909..2837430 100644 --- a/tech_docs/cloud/aws_notes.md +++ b/tech_docs/cloud/aws_notes.md @@ -1,7 +1,127 @@ -When troubleshooting live production environments, **minimizing disruption** is critical. Here’s where to exercise caution and best practices to avoid downtime or broken connections: +You're absolutely right—**using the AWS Console (GUI) is often the fastest and most intuitive way to analyze Flow Logs**, especially for SMEs who need quick answers. Let me correct my earlier CLI-heavy approach and give you the **practical GUI workflow** that AWS network experts actually use. --- +### **Step-by-Step: Troubleshooting with Flow Logs in the AWS Console** +#### **1. Enable Flow Logs (GUI Method)** +1. Go to **VPC Dashboard** → **Your VPC** → Select VPC → **Actions** → **Create Flow Log**. +2. Choose: + - **Filter**: `ALL` (accepts + rejects), `REJECT` (only blocks), or `ACCEPT` (only allows). + - **Destination**: Send to **CloudWatch Logs** (for real-time queries) or **S3** (for long-term storage). + - **Log Format**: Default works, but advanced users add custom fields (e.g., `${tcp-flags}`). + + ![Enable Flow Logs](https://docs.aws.amazon.com/vpc/latest/userguide/images/flow-logs-create.png) + *No CLI needed—just 3 clicks.* + +--- + +#### **2. Analyze Flow Logs in CloudWatch Logs Insights** +**Where GUI Beats CLI:** +- **No query syntax memorization** → Pre-built queries. +- **Visual filtering** → Click-to-analyze. + +**Steps:** +1. Go to **CloudWatch** → **Logs Insights**. +2. Select your **Flow Logs group** (e.g., `VPCFlowLogs`). + +##### **Key Pre-Built Queries (Click + Run)** +###### **A. "Why is my traffic blocked?"** +```sql +fields @timestamp, srcAddr, dstAddr, dstPort, action +| filter action = "REJECT" +| sort @timestamp desc +| limit 50 +``` +*GUI Advantage:* Hover over `REJECT` entries to see blocked ports/IPs instantly. + +###### **B. "Who’s talking to this suspicious IP?"** +```sql +fields @timestamp, srcAddr, dstAddr, bytes +| filter dstAddr = "54.239.25.200" # Example: AWS external IP +| stats sum(bytes) as totalBytes by srcAddr +| sort totalBytes desc +``` +*GUI Advantage:* Click on `srcAddr` to drill into specific instances. + +###### **C. "Is my NAT Gateway working?"** +```sql +fields @timestamp, srcAddr, dstAddr, action +| filter srcAddr like "10.0.1." and dstAddr like "8.8.8." +| stats count(*) by bin(5m) # Traffic volume over time +``` +*GUI Advantage:* Switch to **Visualization** tab to see graphs. + +--- + +#### **3. Visualize Traffic Patterns (No CLI)** +1. In **CloudWatch Logs Insights**, run a query. +2. Click **Visualization** → Choose: + - **Bar chart**: Top talkers (e.g., `stats count(*) by srcAddr`). + - **Time series**: Traffic spikes (e.g., `stats sum(bytes) by bin(1h)`). + + ![CloudWatch Visualization](https://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/images/CWL-Insights-Visualization.png) + +--- + +### **When to Use GUI vs. CLI for Flow Logs** +| **Scenario** | **GUI (Console)** | **CLI** | +|-----------------------------|--------------------------------------------|------------------------------------------| +| **One-off troubleshooting** | ✅ Faster (pre-built queries, point+click) | ❌ Overkill | +| **Daily audits** | ✅ Logs Insights + dashboards | ❌ Manual queries slow | +| **Automation (e.g., SOC)** | ❌ Not scalable | ✅ Script with `aws logs start-query` | +| **Deep packet analysis** | ❌ Limited to metadata | ✅ Pipe logs to Athena/S3 for SQL queries| + +--- + +### **Pro Tips for GUI-Based SMEs** +1. **Save Queries**: Click **Save** → **Add to dashboard** for recurring checks. +2. **Alerts**: Create CloudWatch Alerts for anomalies (e.g., spike in `REJECT`). + - Example: Alert if >100 `REJECT`s in 5 mins. +3. **Cross-Account Flow Logs**: Use **Centralized Logging Account** for multi-VPC views. + +--- + +### **Real-World Example: Troubleshooting a Broken NAT Gateway** +**Symptoms**: Instances in private subnet can’t reach the internet. + +**GUI Flow:** +1. **Flow Logs Query**: + ```sql + fields @timestamp, srcAddr, dstAddr, action + | filter srcAddr like "10.0.1." and dstAddr like "8.8.8." + | sort @timestamp desc + ``` +2. **Findings**: + - If `action = "REJECT"` → Check NACLs. + - If no logs → Check route tables (no path to NAT Gateway). +3. **Fix**: + - GUI route table edit: Add `0.0.0.0/0 → nat-gateway-id`. + +--- + +### **Why GUI Wins for SMEs** +- **No syntax errors**: Pre-built queries reduce mistakes. +- **Speed**: Click-to-insight in seconds (vs. CLI trial/error). +- **Collaboration**: Share CloudWatch dashboards with team. + +**Exception**: Use CLI only if: +- You’re scripting (e.g., nightly security scans). +- AWS Console is down (rare, but happens). + +--- + +### **Final Answer** +Yes, **the GUI (AWS Console + CloudWatch Logs Insights) is the best way to analyze Flow Logs** for most troubleshooting. CLI is for automation—not day-to-day SME work. + +**Actionable Checklist:** +1. ✅ Enable Flow Logs in GUI (VPC → Actions → Create Flow Log). +2. ✅ Use CloudWatch Logs Insights for point+click queries. +3. ✅ Save key queries to dashboards (e.g., `REJECT`ed traffic). +4. ✅ Set alerts for traffic anomalies. + +Want a **screenshot-guided walkthrough** for a specific scenario (e.g., investigating a DDoS attempt)? I can mock up the exact GUI steps. +--- + ### **1. High-Risk Actions That Can Break Traffic** #### **A. Security Group Rule Modifications** - **Risk**: Removing/updating rules can drop active connections.