Intermittent Public IP Detection Failure on 'What is my IP Address' Tool – Seeking Solutions

hey everyone,

we run a simple "What is my IP Address" tool, and it's been getting some traction lately, which is cool. but lately, we're seeing some really intermittent issues where the tool fails to correctly display the user's public IP address. sometimes it shows a local IP (like 192.168.x.x), other times it's just blank. it's not happening for everyone, which makes it super tricky to debug, you know?

here's what we've tried so far:

• checked server logs for any obvious errors or timeouts from our backend IP lookup service. nothing jumps out as consistent.
• tested with different VPNs and proxy services to see if it's related to specific network setups. it's still hit or miss.
• monitored API calls to our external IP detection providers (e.g., ipify, ipinfo.io) – they seem fine on their end, returning valid IPs.
• looked at CDN (Cloudflare) logs to see if certain requests are getting blocked or misrouted, but haven't found a clear pattern.

here's a simplified log snippet from when it fails, just to give you an idea:

[2023-10-27 14:35:01] INFO: Request from 10.0.0.5 (potential internal proxy)
[2023-10-27 14:35:01] WARNING: IP_DETECTION_SERVICE_TIMEOUT for user-agent 'Mozilla/5.0...'
[2023-10-27 14:35:02] ERROR: Failed to parse external IP response: Empty or malformed data.
[2023-10-27 14:35:02] DEBUG: Client IP sent to frontend: 'undefined'

this is a simplified log, but it gives an idea of what we're seeing when it fails.

i'm really hoping someone here has faced something similar. any thoughts on:

• are there common pitfalls with X-Forwarded-For or CF-Connecting-IP headers that could cause this sort of intermittent problem?
• any recommendations for more robust server-side IP detection methods that might be more reliable?
• could it be a specific browser or network configuration issue for a subset of users that we're missing?

thanks in advance for any insights!