"Resolved" Connection is reset

Recently, because of the CC attack site, I moved the site to the cloud ECS, environment configuration: linux+nginx+php, the database is used separately is the cloud RDS, the firewall is using Ali's Web application firewall. Once the deployment is complete, access to the Web site occasionally appears "connection is reset".

Steps to resolve:

1. Route tracking (tracert), found to be able to reach the server, basically ruled out the problem of the line.

2. Check 80 port (TRACETCP), local port connectivity test, test results also no problem (attached: tracetcp use method https://help.aliyun.com/knowledge_detail/40572.html).

3. Check the firewall, before I change the firewall's cc protection mode to "emergency", is the "emergency" mode of the site caused by manslaughter, so I changed firewall protection mode to "normal", again visit the site, found that most of the page is no longer "connection is reset" phenomenon, However, in some specific pages (form submission) or there will be a connection is reset phenomenon Ah, query data, found to be client_max_body_size This parameter problem, in Nginx configuration file (nginx.conf), add this parameter: Client_max_ Body_size 30M, re-access, problem solving.

4. On-line query information said if the use of Proxy server, a similar problem, the introduction of the following code in the configuration file can be resolved (note: not personally verified).

Proxy_set_header Host $host;
Proxy_set_header x-forwarded-for $proxy _add_x_forwarded_for;

"Resolved" Connection is reset