How to resolve Indy DoMaxConnectionsExceeded

Question

I have created a webserver using Delphi2007 and Indy10.

The server runs fine initially, but after time (usually between 8 and 48 hours) the DoMaxConnectionsExceeded method begins to fire; and my web server no longer works properly. Currently I have MaxConnections set to 500. I have experimented in the past with changing this setting. And it does seem the larger the value the longer the web server will live. So it makes me think connections are not being released.

1. Am I doing something wrong in my instantiation? Why are connections not being released?
2. Is there a way to get a list of all connections (by doing this I can check ip addresses and see if it might be DOS attack). Also a way to get the url they are trying to hit?
3. I have also experimented with the KeepAlive property with no change.
4. Should I set MaxConnections to 0?

Source Code for instantiating the TIdHTTPServer:

IdHTTPServer1 := TIdHTTPServer.Create;
IdHTTPServer1.MaxConnections := 500;
IdHTTPServer1.AutoStartSession := True;
IdHTTPServer1.KeepAlive := FGlobalKeepAlive;
IdHTTPServer1.SessionState := True;
IdHTTPServer1.OnCommandGet := IdHTTPServer1CommandGet;
IdHTTPServer1.onexception := IdHttpServerexception;
IdHTTPServer1.onlistenexception := IdHttpServerlistenexception;
idHttpServer1.ParseParams := True;
idHttpServer1.OnQuerySSLPort := QuerySSLPort;
idHttpServer1.IOHandler := ServerIOHandler;
idHttpServer1.Bindings.Add.Port := 80;
idHttpServer1.Bindings.Add.Port := 443;
IdHTTPServer1.Active := True;

Update - want to add I suspect it might be related to SSL. I have similar Indy based web servers that don't need SSL. While they do periodically fail, they don't fail nearly as often. But with these I am not logging DoMaxConnectionsExceeded. I will add tracking of this event to see if and when they do fail it is because maxconnections is exceeded.

Answer 1

Found out what was wrong. While I had set KeepAlive to false on the idHTTPServer component, in another area I was manually setting it on the ResponseInfo:

  Aresponseinfo.Connection:='keep-alive';