When I use a tcp socket to connect to remote host, I may get an "actively refused"

WSAECONNREFUSED == 10061

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or "time out" error in 1st time.

WSAETIMEDOUT == 10060

...

Then when I retry to connect to remote host, I "always" got "Software caused connection abort"

WSAECONNABORTED == 10053

http://msdn.microsoft.com/en-us/library/ms740668%28VS.85%29.aspx

I don't know why you say the former two are "normal" -- actually all the tree mean that there's a problem with your host sockets: either there's no listening socket or it closes an accepted socket, or there's some other issue in the host.

Thanks a lot for helping. I'm still a newbie in asio/socket programming. The socket may be used to connect to a remote host behind NAT which may send back a RST packet or silently drop it. This is expected response. It seems "Software caused connection abort" error is related to my program. The document you pointed confirms this: "An established connection was aborted by the software in your host computer, possibly due to a data transmission time-out or protocol error." The way I use can be sketched by: ============================ open a tcp socket bind to a port asynchronously connect to a remote host in callback if it fails (may get expected errors), asynchronously reconnect to remote host, up to specified times In callback I get "abort" error after every reconnect Any further help to debug this is appreciated.

...

The way I use can be sketched by: ============================ open a tcp socket bind to a port asynchronously connect to a remote host in callback if it fails (may get expected errors), asynchronously reconnect to remote host, up to specified times In callback I get "abort" error after every reconnect

Any further help to debug this is appreciated.

I guess the server (host) closes the connection for some reason, so you have to debug your server and see what happens there after an incoming connection is accepted.

BTW, there's a dedicated asio mailing list: http://news.gmane.org/group/gmane.comp.lib.boost.asio.user

Thanks. This is very helpful information. I found the direct reason. After a failed connect, the socket has been somehow closed. So reconnect cannot be carried out.