HTTP 499 recorded in Cloudflare but not in Nginx Logs
We're randomly experiencing legit requests being served HTTP 499 by Cloudflare. They were not logged by Nginx, meaning the requests never reached the origin. Not due to caching. What can I do to find out the root cause?
9 Replies
Could you first check the response headers to see where the 499 is coming from?
@Laudian how do I check the response headers from Cloudflare?
@Leo I only see the 499s from Cloudflare's Analytics & Logs > HTTP Traffic.
seeing 499s in the analytics is normal and expected, client connections will break abruptly for a variety of legitimate reasons. unless your users are reporting seeing them in their browser, there's nothing to worry about
But it's disruptive. My payment gateway, Xendit is reporting random timeouts when trying to connect to my endpoint. My Nginx didn't log those requests, meaning they timed out at Cloudflare.
I understand that Cloudflare has a default timeout of 30 seconds. Why would it take longer than that to reach my Nginx which is the origin?
You're not understanding their messages
499 is the Client disconnecting, not the Server/Cloudflare giving up.
The most common hit timeout is the Proxy Read timeout (Cloudflare waiting for your origin response) which is 100 seconds, and would show as 524 if hit. https://developers.cloudflare.com/fundamentals/reference/connection-limits/
Xendit is giving up/disconnecting for some reason, perhaps on their end they have a hard timeout at something fast, like 5 seconds, or some persistent network issue with them. You could ask them of their timeouts and if they have any more info.
https://help.xendit.co/hc/en-us/articles/360038049331-How-Do-I-Reconcile-My-Webhook-through-Webhook-Tab#:~:text=xendit%20did%20not%20receive%20any%20response%20from%20your%20server%20within%2030s
According to their documentation, their timeout is 30s, so that's why I'm questioning why within 30 seconds Cloudflare didn't forward the requests to my origin.
Xendit Help Center
How Do I Reconcile My Webhook through Webhook Tab?
You can use our Webhook Tab to reconcile your webhooks
Webhook Tab Functions
Through Webhook Tab, you can:
See the history of webhook that Xendit sends to your assigned webhook URL;
See the indiv...
What do you see in Xendit exactly, the
Timeout status or a response with a specific http status?
If it is a http response and you can see response headers, seeing if CF-Cache-Status exists would be helpfulThe timeout info includes, timestamp, URL and the message below:
I can't see
CF-Cache-Status unfortunately.Makes sense since not an http response.
So Xendit thinks the request took too long, and they hard killed it. Cloudflare sees that as a 499, since Xendit disconnected early
Just gotta find out why your origin takes so long sometimes then. Do you have any rules or anything in Cloudflare (Workers, etc), setup on the webhook handling endpoint? You can use the "Trace" util within Cloudflare if you're not sure. Should be also able to look in your nginx normal logs for 499 client disconnects, and at potentially other logs