---
title: Troubleshooting
sidebar_position: 100
---

We have collected solutions to common issued faced by web mirrors users.
If you are unable to resolve your issue, please [get in touch](https://www.sr2.uk/contact) with us to discuss the options.

## Upstream Rate Limiting

CDNs (Content Delivery Networks) can impose rate limiting or "bot detection" on websites to ensure that the network
resources are efficiently utilized, to protect the websites from Denial of Service (DoS) attacks, and to
maintain the quality of service for all the websites using the CDN.
If you find that mirrors are producing many “Rate Limited Exceeded” or “Access Denied” errors then you may be suffering
from this problem.

These rate limits will be sized according to the expected rate of requests from an average user, however the mirror
system is a bottleneck that aggregates requests from multiple users and passes these on to the original CDN.
When a single system is used to send a large number of requests to a CDN like this, the CDN may interpret this as a
DoS attack and prevent access to the website.

The optimal approach is to configure the origin to use an alternative host for connections, so that the CDN is bypassed
and the backend origin (web server) is used directly.
The mirror will still be the access point for users and this will not reveal the location of the backend origin to your
users.

If this is not possible, then deploying mirrors for websites hosted on CDNs will require either configuration at, or
co-operation from, the CDN provider.
Additional headers can be configured for the origin to authenticate requests that originate from the mirrors, and these
can be used to bypass the protection mechanisms at your CDN.
Consult your CDN's documentation or contact their support team to configure using an additional header to disable the
rate limiting for requests originating from the mirrors.