[AGM-2231] Add an article about Rate limit to KB

docs/private-dns/server-and-settings/rate-limit.md

@@ -0,0 +1,23 @@
+---
+title: Rate limit
+sidebar_position: 4
+---
+
+DNS rate limiting is a method used to control the amount of traffic that a DNS server can process in a certain timeframe.
+
+Without rate limits, DNS servers are vulnerable to being overloaded, and as a result, users might encounter slowdowns, interruptions, or complete downtime of the service. Rate limiting ensures that DNS servers can maintain performance and uptime even under heavy traffic conditions. Rate limits also help to protect you from malicious activity, such as DoS and DDoS attacks.
+
+## How does Rate limit work
+
+DNS rate-limiting typically works by setting thresholds on the number of requests a client (IP address) can make to a DNS server over a certain time period. If you're having issues with the current AdGuard DNS rate limit and are on a *Team* or *Enterprise* plan, you can request a rate limit increase.
+
+## How to request DNS rate limit increase
+
+If you are subscribed to AdGuard DNS *Team* or *Enterprise* plan, you can request a higher rate limit. To do so, please follow the instructions below:
+
+ 1. Go to [DNS dashboard](https://adguard-dns.io/dashboard/) → *Account settings* → *Rate limit*
+ 1. Tap *request a limit increase* to contact our support team and apply for the rate limit increase. You will need to provide your CIDR and the limit you want to have
+
+ ![Rate limit](https://cdn.adtidy.org/content/kb/dns/private/rate_limit.png)
+
+ 1. Your request will be reviewed within 1-3 working days. We will contact you about the changes by email

docs/public-dns/overview.md

@@ -43,3 +43,7 @@ Unlike with Google DNS, AdGuard DNS doesn't support `edns_client_subnet` and `Co
 ### DNS-over-QUIC (DoQ)
 
 [DNS-over-QUIC is a new DNS encryption protocol](https://adguard.com/blog/dns-over-quic.html) and AdGuard DNS is the first public resolver that supports it. Unlike DoH and DoT, it uses QUIC as a transport protocol and finally brings DNS back to its roots — working over UDP. It brings all the good things that QUIC has to offer — out-of-the-box encryption, reduced connection times, better performance when data packets are lost. Also, QUIC is supposed to be a transport-level protocol and there are no risks of metadata leaks that could happen with DoH.
+
+### Rate limit
+
+DNS rate limiting is a technique used to regulate the amount of traffic a DNS server can handle within a specific time period. We offer the option to increase the default limit for Team and Enterprise plans of Private AdGuard DNS. For more information, please [read the related article](/private-dns/server-and-settings/rate-limit.md).