SMTP authentication in mail servers

coder47secarc · 12-14-2008, 06:31 AM

Hi,

I am trying to send a mail to a yahoo account through telnet.
Can anyone help me out as whenever I say

MAIL FROM: abc@xyz.com

the connection is terminated saying Authentication Required.

thanks in advance.

**johnwill** · 12-14-2008, 09:33 AM

I don't have any idea how you'd send mail using Telnet, how about explaining the whole environment?

coder47secarc · 12-14-2008, 10:26 AM

sorry.... i was not referring to telnet service , i was only asking how to achieve the same by telnetting to the SMTP port of the server.

like:

TELNET smtp.mail.yahoo.com 25

**johnwill** · 12-15-2008, 09:28 AM

I have no idea, never even heard of anyone trying to do that. I suspect due to the SMTP protocol, this would not be easy.

grue155 · 12-16-2008, 05:06 PM

You're trying a raw SMTP connection? Okay...

So what does the SMTP exchange look like?

On the dayjob servers here, authorization can be done only within an TLS connection. After the EHLO, is STARTTLS one of the available options? If not, then you probably are connecting on the wrong port (TCP 25 is for mail relay), and probably need to connect to TCP port 587.

12-14-2008, 06:31 AM	#1 (permalink)
coder47secarc Registered User Join Date: Dec 2008 Posts: 2 OS: windows xp service pack 2	SMTP authentication in mail servers Hi, I am trying to send a mail to a yahoo account through telnet. Can anyone help me out as whenever I say MAIL FROM: abc@xyz.com the connection is terminated saying Authentication Required. thanks in advance.

12-14-2008, 09:33 AM	#2 (permalink)
johnwill Manager, Networking Forums Join Date: Sep 2002 Location: S.E. Pennsylvania, US Posts: 41,787 OS: Windows 7, XP-Pro, Vista, Linux Blog Entries: 1	Re: SMTP authentication in mail servers I don't have any idea how you'd send mail using Telnet, how about explaining the whole environment? __________________ If TSF has helped you, Tell us about it! or Donate to help keep the site up! Microsoft MVP - Windows Desktop Experience

12-14-2008, 10:26 AM	#3 (permalink)
coder47secarc Registered User Join Date: Dec 2008 Posts: 2 OS: windows xp service pack 2	Re: SMTP authentication in mail servers sorry.... i was not referring to telnet service , i was only asking how to achieve the same by telnetting to the SMTP port of the server. like: TELNET smtp.mail.yahoo.com 25

12-15-2008, 09:28 AM	#4 (permalink)
johnwill Manager, Networking Forums Join Date: Sep 2002 Location: S.E. Pennsylvania, US Posts: 41,787 OS: Windows 7, XP-Pro, Vista, Linux Blog Entries: 1	Re: SMTP authentication in mail servers I have no idea, never even heard of anyone trying to do that. I suspect due to the SMTP protocol, this would not be easy. __________________ If TSF has helped you, Tell us about it! or Donate to help keep the site up! Microsoft MVP - Windows Desktop Experience

12-16-2008, 05:06 PM	#5 (permalink)
grue155 Registered User Join Date: May 2008 Posts: 240 OS: LAN Herder	Re: SMTP authentication in mail servers You're trying a raw SMTP connection? Okay... So what does the SMTP exchange look like? On the dayjob servers here, authorization can be done only within an TLS connection. After the EHLO, is STARTTLS one of the available options? If not, then you probably are connecting on the wrong port (TCP 25 is for mail relay), and probably need to connect to TCP port 587.