Linux - Server This forum is for the discussion of Linux Software used in a server related context. |
Notices |
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
Are you new to LinuxQuestions.org? Visit the following links:
Site Howto |
Site FAQ |
Sitemap |
Register Now
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Get a virtual cloud desktop with the Linux distro that you want in less than five minutes with Shells! With over 10 pre-installed distros to choose from, the worry-free installation life is here! Whether you are a digital nomad or just looking for flexibility, Shells can put your Linux machine on the device that you want to use.
Exclusive for LQ members, get up to 45% off per month. Click here for more info.
|
 |
|
06-14-2013, 03:55 AM
|
#1
|
Member
Registered: May 2012
Posts: 58
Rep: 
|
telnet to smtp SERVER
can anyone give a working example for telnet to smtp server.
i tried this
telnet mail.isp.com 25
here the remote host rejecting my connection.
i tried
telnet smtpcorp.com 25
its connecting but failed to send mail.
my aim is to send an email using these technique. pls help me,this is for my study purpose only,
|
|
|
06-14-2013, 04:26 AM
|
#2
|
Member
Registered: Oct 2012
Distribution: OpenSuSE,RHEL,Fedora,OpenBSD
Posts: 982
|
You can get a reasonable idea what the conversation looks like using what is displayed by sendmail -v .
|
|
|
06-14-2013, 04:38 AM
|
#3
|
Senior Member
Registered: Jan 2012
Distribution: Slackware
Posts: 3,349
Rep: 
|
The SMTP protocol itself it fairly simple: You start with HELO or EHLO, state the sender address with the MAIL TO command, specify the recipient with the RCPT TO command, and finally send the mail itself with the DATA command.
Most SMTP servers will refuse mail from blacklisted IP addresses, which usually include all IP ranges used by ISPs for dynamic address assignment. Some servers will accept the connection but reject the mail, while others refuse the TCP connection altogether. Also, your mails may be rejected by a number of anti-spam measures.
ISP mail relays are increasingly using the mail submission port (587) rather than port 25, usually in combination with StartTLS and forced authentication.
|
|
1 members found this post helpful.
|
06-14-2013, 05:51 AM
|
#4
|
Member
Registered: Feb 2008
Distribution: Fedora,RHEL,Ubuntu
Posts: 661
Rep:
|
Quote:
telnet smtpcorp.com 25
ehlo testmachine
mail from: <sender mail id>
rcpt to: <receiver mail id>
data
How are you? (Mail Body)
.
|
Above command will help you.
Thanks
|
|
1 members found this post helpful.
|
06-14-2013, 08:06 AM
|
#5
|
Member
Registered: May 2012
Posts: 58
Original Poster
Rep: 
|
Quote:
Originally Posted by Ser Olmy
The SMTP protocol itself it fairly simple: You start with HELO or EHLO, state the sender address with the MAIL TO command, specify the recipient with the RCPT TO command, and finally send the mail itself with the DATA command.
Most SMTP servers will refuse mail from blacklisted IP addresses, which usually include all IP ranges used by ISPs for dynamic address assignment. Some servers will accept the connection but reject the mail, while others refuse the TCP connection altogether. Also, your mails may be rejected by a number of anti-spam measures.
ISP mail relays are increasingly using the mail submission port (587) rather than port 25, usually in combination with StartTLS and forced authentication.
|
so how i can become whitelist ip address. what is the other ways to send mail in this way if am blacklisted.
|
|
|
06-14-2013, 08:26 AM
|
#6
|
Senior Member
Registered: Jan 2012
Distribution: Slackware
Posts: 3,349
Rep: 
|
Quote:
Originally Posted by mr.cracker
so how i can become whitelist ip address. what is the other ways to send mail in this way if am blacklisted.
|
If you're running a mail server and have been assigned a fixed, public IP address, and the host name is registered as a mail exchanger for the domain of the sender, you should be able to send mail anywhere. Ideally, you should also create Sender Policy Framework records in DNS.
However, if you're a regular broadband customer with a dynamic IP address, that address cannot be whitelisted, as blacklist providers such as SpamCop and Spamhaus just don't allow it. This is a Good Thing, as it helps prevent spam.
You will most likely have to use the relay server provided by the ISP. As I mentioned, this server may use the Mail Submission port rather than the standard SMTP port, and may require authentication and StartTLS, the latter of which rules out using a telnet client to send e-mails.
|
|
1 members found this post helpful.
|
06-14-2013, 08:33 AM
|
#7
|
Member
Registered: May 2012
Posts: 58
Original Poster
Rep: 
|
Quote:
Originally Posted by vishesh
Above command will help you.
Thanks
|
i tried but it gave,
550 relay refused myname101@yahoo.com/117.217.236.100 unauthenticated
what wil i do?
Last edited by mr.cracker; 06-14-2013 at 08:34 AM.
|
|
|
06-14-2013, 08:35 AM
|
#8
|
Member
Registered: May 2012
Posts: 58
Original Poster
Rep: 
|
Quote:
Originally Posted by linosaurusroot
You can get a reasonable idea what the conversation looks like using what is displayed by sendmail -v .
|
i didnt get!
|
|
|
06-14-2013, 08:38 AM
|
#9
|
Senior Member
Registered: Jan 2012
Distribution: Slackware
Posts: 3,349
Rep: 
|
Quote:
Originally Posted by mr.cracker
i tried but it gave,
550 relay refused myname101@yahoo.com/117.217.236.100 unauthenticated
what wil i do?
|
The error message makes it pretty clear that the server requires authentication.
|
|
1 members found this post helpful.
|
06-14-2013, 10:21 AM
|
#10
|
Member
Registered: Feb 2008
Distribution: Fedora,RHEL,Ubuntu
Posts: 661
Rep:
|
When you execute below command you will get list of commands features by MTA, what are those commands
Quote:
telnet smtpcorp.com 25
ehlo testmachine
|
Thanks
|
|
1 members found this post helpful.
|
06-14-2013, 10:18 PM
|
#11
|
Member
Registered: May 2012
Posts: 58
Original Poster
Rep: 
|
Quote:
Originally Posted by vishesh
When you execute below command you will get list of commands features by MTA, what are those commands
Thanks
|
sorry not tat also not working ! any other sugestions 
|
|
|
06-15-2013, 09:54 PM
|
#12
|
LQ Newbie
Registered: Jul 2008
Location: Hyderabad,India
Distribution: Redhat,CentOS,Ubuntu
Posts: 17
Rep:
|
Hi Mr.Cracker,
Check the smtp port number and check the service is running or not then try to telnet using that port number.
--
Mahesh Saga
System Administrator,
+91 77 02 445511
<moderated>
Last edited by colucix; 06-22-2013 at 02:59 AM.
Reason: Removed link to totally unrelated site
|
|
|
06-16-2013, 11:03 AM
|
#13
|
LQ Guru
Registered: Jul 2003
Location: Birmingham, Alabama
Distribution: SuSE, RedHat, Slack,CentOS
Posts: 27,788
|
Quote:
Originally Posted by mahesh.saga
Hi Mr.Cracker,
Check the smtp port number and check the service is running or not then try to telnet using that port number.
|
The port is obviously correct, since they were able to connect to it WITH telnet. Did you not read any of the previous posts???
Ser Olmy answered the question in post #6. OP, you're going to have to work with your ISP, unless you're running your own mail server in accordance with the guidelines of your provider.
|
|
1 members found this post helpful.
|
06-18-2013, 11:20 PM
|
#14
|
Member
Registered: May 2012
Posts: 58
Original Poster
Rep: 
|
Quote:
Originally Posted by vishesh
When you execute below command you will get list of commands features by MTA, what are those commands
Thanks
|
i got this,
ehlo testmachine
250-smtpcorp.com Hello testmachine [117.196.163.244]
250-SIZE 52428800
250-PIPELINING
250-AUTH CRAM-MD5 PLAIN LOGIN
250-STARTTLS
250 HELP
|
|
|
06-18-2013, 11:26 PM
|
#15
|
Member
Registered: May 2012
Posts: 58
Original Poster
Rep: 
|
Quote:
Originally Posted by Ser Olmy
The error message makes it pretty clear that the server requires authentication.
|
HOW I WILL ACHIEVE AUTHENTICATION.
I TYPED GOT THE FOLLOWING,
AUTH CRAM-MD5
334 PDM0ODUuMTM3MTYxNTc1OEBzbXRwY29ycC5jb20+
AUTH PLAIN LOGIN
HELP
1501 Invalid base64 data
HELP AUTH
214-Commands supported:
214 AUTH STARTTLS HELO EHLO MAIL RCPT DATA NOOP QUIT RSET HELP
AUTH
500 unrecognized command
|
|
|
All times are GMT -5. The time now is 03:58 PM.
|
LinuxQuestions.org is looking for people interested in writing
Editorials, Articles, Reviews, and more. If you'd like to contribute
content, let us know.
|
Latest Threads
LQ News
|
|