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Incident Response
Guide

Network Incident Response Playbook for Development Teams

A practical guide to handling network-related production incidents when you don't have a dedicated network team.

whisperly Team
18 min read
December 15, 2023

The Reality for Most Teams

Most development teams don't have dedicated network engineers. When production goes down due to network issues, you're often on your own. This playbook gives you a systematic approach to diagnosing and resolving network incidents quickly.

Understanding Network Incidents

Network incidents can manifest in many ways, but they often share common characteristics:

Common Network Incident Symptoms

Performance Issues

  • Slow Response Times

    API calls taking much longer than normal

  • Intermittent Failures

    Requests sometimes work, sometimes fail

  • High Latency

    Increased time between request and response

Connectivity Issues

  • Connection Timeouts

    Unable to establish connections to services

  • Service Unreachable

    Services appear completely offline

  • DNS Resolution Failures

    Unable to resolve domain names to IP addresses

Incident Response Framework

Follow this structured approach to handle network incidents effectively:

1

Initial Assessment

Quickly determine the scope and nature of the problem:

Confirm the issue

Verify that the problem is real and not a false alarm

Assess impact

Determine how many users or services are affected

Identify scope

Is it affecting all services or just specific ones?

Gather initial data

Collect error messages, logs, and basic metrics

2

Problem Isolation

Narrow down where the problem is occurring:

Divide and conquer

Test connectivity at different layers (application, transport, network)

Eliminate possibilities

Rule out application-level issues before diving into network debugging

Test from multiple locations

Determine if the problem is localized or widespread

3

Data Collection

Gather the information needed to diagnose the issue:

Application logs

Error messages, stack traces, and timing information

System metrics

CPU, memory, disk, and network usage data

Network captures

PCAP files for detailed network analysis

Infrastructure state

Recent changes, deployments, or configuration updates

4

Root Cause Analysis

Use the collected data to identify the underlying cause:

Correlate events

Look for patterns between the incident and recent changes

Analyze network data

Examine PCAP files for anomalies like retransmissions or timeouts

Validate hypotheses

Test theories with targeted experiments or checks

5

Resolution and Verification

Implement the fix and confirm it resolves the issue:

Apply minimal fixes

Make the smallest change possible to restore service

Verify the fix

Confirm the issue is resolved from multiple perspectives

Monitor for regressions

Watch for any unintended side effects of the fix

6

Post-Incident Activities

Learn from the incident to prevent future occurrences:

Document findings

Create a detailed incident report with timeline and root cause

Implement preventive measures

Add monitoring, improve documentation, or update processes

Share knowledge

Present findings to the team and update runbooks

Real-World Case Study: The Great Timeout Outage

Here's how a development team handled a major network incident:

Incident Timeline

09:15

Incident Detected

Monitoring alerts fire: "API response time exceeded 10s threshold"

09:20

Initial Assessment

Team confirms issue affects 80% of API requests. Database appears healthy.

09:35

Problem Isolation

Network tests reveal high latency and packet loss between app servers and database.

09:50

Data Collection

Capture PCAP files showing 15% packet loss and 3x normal latency.

10:05

Root Cause Analysis

Infrastructure team identifies faulty network switch causing the packet loss.

10:25

Resolution

Faulty switch is replaced. Service fully restored within 10 minutes.

Key Lessons Learned

1
Network issues masquerade as application problems

Slow database queries were actually slow network responses

2
PCAP analysis was crucial

Packet captures clearly showed the network-level issues

3
Cross-team collaboration was essential

Development team provided application context; infrastructure team fixed hardware

Essential Tools for Network Incident Response

Having the right tools ready can significantly reduce incident response time:

Command-Line Tools

  • ping/traceroute

    Basic connectivity and path testing

  • nslookup/dig

    DNS resolution testing

  • tcpdump/tshark

    Network packet capture and analysis

  • ss/netstat

    Network connection state inspection

Specialized Tools

  • Wireshark

    GUI-based deep packet analysis

  • whisperly

    AI-powered network issue diagnosis

  • nmap

    Network discovery and security auditing

  • iperf

    Network bandwidth and performance testing

Network Incident Response Checklist

Use this checklist during network incident response:

Preparation

Document network architecture and dependencies
Maintain list of critical network endpoints
Ensure access to network analysis tools
Create escalation contacts for infrastructure team

During Incident

Preserve evidence (logs, PCAP files)
Communicate status to stakeholders
Test hypotheses systematically
Document findings in real-time

Post-Incident

Write detailed incident report
Identify and implement preventive measures
Update runbooks and documentation
Share lessons learned with the team

Continuous Improvement

Regularly test incident response procedures
Review and update tools and playbooks
Train new team members on procedures
Participate in cross-team incident drills

Prevention Strategies

While you can't prevent all network incidents, these strategies reduce their likelihood and impact:

Proactive Monitoring

  • Monitor network latency and packet loss
  • Set alerts for DNS resolution failures
  • Track TCP connection establishment times
  • Monitor for unusual traffic patterns

Resilience Engineering

  • Implement circuit breakers for external dependencies
  • Use retry logic with exponential backoff
  • Design for graceful degradation
  • Implement health checks for all services

Tooling and Automation

  • Automate network testing in CI/CD pipelines
  • Use infrastructure-as-code for consistent deployments
  • Implement canary deployments for network changes
  • Use service meshes for advanced traffic management

Knowledge Management

  • Maintain up-to-date network diagrams
  • Document common network troubleshooting procedures
  • Create runbooks for frequent network issues
  • Regularly review and update incident response plans

Get Instant Network Incident Diagnosis

Upload your PCAP file to whisperly and get AI-powered analysis of network incidents. Reduce mean time to resolution by 80%.

Try whisperly - Free Incident AnalysisIncident Response Guide

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