Problems and solutions when using WAF - Web Application Firewall

This topic addresses frequently asked questions about Web Application Firewall (WAF).

Category	Questions
Product FAQ	Website access configuration Can a domain name be added to WAF in both transparent proxy mode and CNAME mode? What do I do if a domain name added in transparent proxy mode no longer requires WAF to forward traffic and provide protection? After I use the transparent proxy mode, can the origin server obtain the real IP addresses of clients? If the certificate bound to a port is updated, do I need to re-upload the certificate to the WAF transparent proxy module? If a domain name is configured on multiple SLB instances, how do I add the domain name in transparent proxy mode? If multiple domain names are configured on an SLB instance, what are the effects if I add only one of the domain names in transparent proxy mode? Why can't I find the Layer 7 SLB instance that I want to add in transparent proxy mode?
Website access topics	Website access issues How do I troubleshoot HTTPS access issues? HTTPS access exceptions caused by SNI compatibility (server certificate not trusted) What to do if an ECS origin server protected by WAF is compromised What do I do if blackhole filtering is triggered for my WAF instance?
Product configuration	Supported domain name suffixes Do unconfigured ports of a protected website pose a security risk to the origin server? Web Application Firewall traffic access diagram CC attack protection: Emergency mode How to troubleshoot and handle 405 status code errors
Fault analysis	What do I do if services on non-standard ports cannot be added to WAF Pro? What do I do if the "Invalid HTTPS private key format" error is reported when I upload an HTTPS certificate? How to troubleshoot a certificate and private key mismatch Web Application Firewall blocking file upload requests How do I resolve logon status loss? What do I do if a persistent connection times out? Why can't I access miniapps after I configure WAF? Why can't some clients access my website after I configure WAF?
Services	Alibaba Cloud DNS versions
Concepts	Definitions of common web vulnerabilities Why can't I directly access the CNAME generated by WAF?