On 4/20/2010 1:23 PM, Linux Addict wrote: > > > On Mon, Apr 19, 2010 at 11:37 AM, Wietse Venema <wie...@porcupine.org > <mailto:wie...@porcupine.org>> wrote: > > Gaby L: > > Hi > > I scan with my postfix server with NMap from other location. > > The NMAP creats report smtp port open (It is OK) but apear > Postfix smtpd and other information about MTA program. > > I dont want to apear any information about my MTA server. > > To disclose no information, close the SMTP port. > > Seriously. > > Even when you change the smtpd_banner value to say "$myhostname > ESMTP Sendmail" (this text MUST start with the hostname), the > server's replies (especially error messages) still reveal that it's > really Postfix. > > Wietse > > > > Disclaimer :- It may violate some RFCs and possibly break the smtp > system itself. > > [r...@stick ~]# grep ^smtpd_banner /etc/postfix/main.cf <http://main.cf> > smtpd_banner = "unknown" > > [r...@stick ~]# telnet 0 25 > Trying 0.0.0.0... > Connected to 0. > Escape character is '^]'. > 220 "unknown" > >
As Wietse mentioned, the above has no effect on determining the server type. Just because the banner doesn't say Postfix, doesn't mean a script/person couldn't figure it out from the response/error messages.
