Automatically check bounced emails via POP3? [closed]

Question

Can anyone recommend software or a .NET library that will check for bounced emails and the reason for the bounce? I get bounced emails into a pop3 account that I can read then.

I need it to keep my user database clean from invalid email addresses and want to automate this (mark user as invalid email).

Answer 1

I have done a great deal of work handling bounce emails and there different types. If you want to be absolutely sure that the email your looking at is indeed a bounce of a specific kind I highly recommend getting a good filter. I have worked with Boogie Tools and it has worked very well. It lets you know what kind of bounce it is, Hard, Soft, Transient or if its even someone trying to unsubscribe. It has a muliple API's including .Net and I found it quite easy to get working.

Answer 2

It's pretty easy to do with a TcpClient. Open the server:

TcpClient tcpClient = new TcpClient();
tcpClient.Connect(POP3Server, POP3Port);
NetworkStream stream = tcpClient.GetStream();

Read the welcome message:

int read = stream.Read(inBuffer, 0, inBuffer.Length);
string response = Encoding.ASCII.GetString(inBuffer, 0, read);
if (response.IndexOf("+OK") != 0) throw new ...;

Write back to the server:

byte[] outBuffer = Encoding.ASCII.GetBytes("USER " + account + "\r\n");
stream.Write(outBuffer, 0, outBuffer.Length);

That sends the USER command. You need to login and then you can start grabbing messages - see the POP3 RFC for the full list of commands. If you're not looking to roll your own check out this CodeProject article.