Diagnostics

These articles describe how to log data, troubleshoot problems, and tune performance.

These articles describe common errors you may encounter when setting up and configuring Fastly services.

• Common 400 errors on Fastly
• Common 503 errors on Fastly
• Common OTFP errors
• Common service and domain errors
• Error 1000 with CloudFlare DNS
• Fixing cross-domain errors
• Loop detection
• TLS certificate errors
• TLS origin configuration messages

Because Fastly doesn't store customer logs, we provide information about debugging techniques that help you gain insights into your service configurations.

• Changing connection timeouts to your origin
• Checking cache
• Debugging with mtr
• Debugging with WebPageTest
• Fastly's service status
• Google Pagespeed module errors
• Googlebot crawl stats
• Temporarily disabling caching
• Using GET instead of HEAD for command line caching tests

These articles describe how we support real-time log streaming of data that passes through Fastly.

• About Fastly's real-time log streaming features
• Changing log compression formats
• Changing log line formats
• Changing log placement
• Changing where log files are written
• Configuring Google IAM service account impersonation to avoid storing keys on Fastly logging
• Creating an AWS IAM role for Fastly logging
• Custom log formats
• Encrypting logs
• Setting up remote log streaming
• Useful conditions for logging
• Useful log formats
• Useful variables to log