Hi All, Only a working and connection accepting Mail Server gives the status 220. And I will be able to know only using telnet. And generally, if any other application (not a mail server) is running in port 25 (just like SSH in port 25) both `nc` and `nmap` shows open but they won't give status 220.
Regards, Kurian Thayil. On Sat, Apr 18, 2009 at 12:18 PM, Tapani Tarvainen < [email protected]> wrote: > On Sat, Apr 18, 2009 at 08:27:43AM +0300, Andrei Popescu ( > [email protected]) wrote: > > > On Sat,18.Apr.09, 08:04:12, Kurian Thayil wrote: > > > > only whether the port is open or not. But what I need is to check if an > > > SMTP server is listening in that port. So I guess the best tool is > > > telnet and to check 220 status. > > > Hhm, I thought a port cannot be "open" unless some server is *listening* > > on that port. What other server do you think would otherwise listen to > > port 25? > > It could be under inetd, which would keep the port open even if it > couldn't actually start the mail server, or there could be a mail > server that's not accepting mail for some reason. > And people do abuse ports - I've even seen ssh in port 25. > > So if the intent is to check if mail could be sent, > checking for smtp reply code is better. > (It's not 100% reliable either, but then nothing is, short of > actually sending the mail and waiting for reply or something.) > > -- > Tapani Tarvainen > > > -- > To UNSUBSCRIBE, email to [email protected] > with a subject of "unsubscribe". Trouble? Contact > [email protected] > >
