Serge Please will you tell me how to protect a server against open relay under the following senario. Users can connect to the server from anywhere. The remote addresses are impossible to know. They could be travelling and using different ISP's to connect from. I have therefore removed the RemoteAddrNotInNetwork matcher as per the hints in the config file <snip> NOTE 3: If you use SMTP AUTH, you may want to comment this so users who are on the road can still use the server </snip> Under the above senario, anyone can send a MAIL FROM:<> message and relay it to whom they choose. Surley this is not correct. How then do you make sure that you don't open your server to allow it to relay those messages?
Andrew On Sun, 2002-06-23 at 06:12, Serge Knystautas wrote: > ----- Original Message ----- > From: "Noel J. Bergman" <[EMAIL PROTECTED]> > > > > > If this can be implemented, the hole can be closed by checking that the > > > MAIL FROM:<> mail originates within the network. > > > > RemoteAddr(Not)InNetwork should cover that aspect. > > > > > Is there a valid reason to accept null senders through the SMTPHandler? > > > > No idea. Ask Serge. I haven't checked the SMTP RFC to see if a null > sender > > is legit. > > Yes, null senders is a very important concept in SMTP handling. Bounce > messages and other system-generated notices often use the null sender. They > can originate from anywhere, not just on the local network. You just want > to make sure you don't open your server to allow it to relay those messages. > > Serge Knystautas > Loki Technologies > http://www.lokitech.com/ > > > -- > To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> > For additional commands, e-mail: <mailto:[EMAIL PROTECTED]> > > -- Andrew Timberlake Digital Design Development http://www.ddd.co.za mailto:[EMAIL PROTECTED] 011 705 1737 082 415 8283 "If debugging is the process of removing bugs, then programming must be the process of putting them in." -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
