Hey there, sorry to hear you're stuck with this frustrating problem—your current IP can't read or write to Firebase, but switching to another IP works perfectly. Let's walk through practical steps to troubleshoot and fix this:

1. Check Firebase's IP Restrictions & Security Rules #

• Head to your Firebase Console and review your Firestore/Realtime Database Security Rules. Did you recently add IP-based allow/deny rules that might exclude your current IP? Double-check for lines like allow read, write: if request.ip == "xxx.xxx.xxx.xxx"; that could be blocking your address.
• Also, check the IP Access Control settings under your project's Cloud Firestore or Storage configuration (if enabled). If you've set up a whitelist, make sure your current IP is included.
• Don't overlook App Check settings—if you're using it to restrict access, it might be inadvertently blocking your IP range.

2. Troubleshoot Local Network/ISP Issues #

• Test basic connectivity to Firebase's endpoints: Run curl -v https://firebase.googleapis.com in your terminal. Look for error messages like connection timeouts, SSL errors, or 403/404 responses—these clues can tell you if your IP is blocked at the network level.
• Flush your local DNS cache to rule out stale records:
  • Windows: Run ipconfig /flushdns in Command Prompt (as admin)
  • Mac: Run sudo dscacheutil -flushcache in Terminal
  • Linux: Run sudo systemd-resolve --flush-caches or sudo service nscd restart depending on your distro
• Reach out to your ISP to ask if they've recently blocked Firebase's domains or IP ranges—temporary network restrictions often cause this kind of issue.

3. Verify Firebase Service Status #

• Check the official Firebase status page to see if there's a regional outage affecting your area. Sometimes service disruptions target specific IP segments, which would explain why switching IPs works.

4. Clear Local SDK/Browser Cache #

• For web apps: Clear your browser's cache and cookies, or test in incognito mode to rule out cached credentials or settings.
• For backend apps (Node.js, etc.): Restart your application and clear any cached dependencies (like deleting node_modules and reinstalling—this is a more drastic step, but worth trying if other fixes fail).

5. Check Quotas & Permissions #

• Even though switching IPs works, quickly verify your project's Usage & Billing page in Firebase Console. Make sure you haven't hit any read/write quotas—while this usually affects all IPs, it's a quick check to rule out edge cases.
• Confirm your service account keys (if using server-side SDKs) are still valid and have the necessary permissions. Expired or revoked keys could cause issues, though this would likely affect all IPs.

If none of these steps resolve the issue, gather detailed error logs (like exact SDK error messages, curl command output, and timestamps) and submit a support ticket through the Firebase Console. These details will help the team pinpoint whether your IP is blocked by Firebase's systems or something else.

内容的提问来源于stack exchange，提问作者HARSH ASHRA