How to Test SMTP AUTH using Telnet
Below are instructions on how to test SMTP AUTH against a mail server using Telnet and entering the commands by hand.
The first thing you need to do is get a base64 encoding of your username and password. There are a couple ways to do this, the example below uses Perl:
perl -MMIME::Base64 -e 'print encode_base64("username");' perl -MMIME::Base64 -e 'print encode_base64("password");'
What will be returned from each command is a base64 encoding of the username and password; save these as you will need them later. Now connect to the mail server using Telnet:
telnet mailserver.com 25
Greet the mail server:
EHLO mailserver.com
Tell the server you want to authenticate with it:
AUTH LOGIN
The server should have returned 334 VXNlcm5hbWU6;
this is a base64 encoded string asking you for your username, paste the base64 encoded username you created earlier, example:
dXNlcm5hbWUuY29t
Now the server should have returned 334 UGFzc3dvcmQ6;
. Again this is a base64 encoded string now asking for your password, paste the base64 encoded password you created, example:
bXlwYXNzd29yZA==
Now you should have received a message telling you that you successfully authenticated. If it failed your user/pass may have been wrong or your mailserver is broken.
Below is a log of a real successful SMTP AUTH connection over Telnet:
user@localhost [~]# telnet exampledomain.com 25 Trying 1.1.1.1... Connected to exampledomain.com (1.1.1.1). Escape character is '^]'. 220-server1.exampledomain.com ESMTP Exim 4.66 #1 Wed, 09 May 2007 23:55:12 +0200 220-We do not authorize the use of this system to transport unsolicited, 220 and/or bulk e-mail. EHLO exampledomain.com 250-server1.exampledomain.com Hello [1.1.1.2] 250-SIZE 52428800 250-PIPELINING 250-AUTH PLAIN LOGIN 250-STARTTLS 250 HELP AUTH LOGIN 334 VXNlcm5hbWU6 dXNlcm5hbWUuY29t 334 UGFzc3dvcmQ6 bXlwYXNzd29yZA== 235 Authentication succeeded
번호 | 분류 | 제목 | 글쓴이 | 날짜 | 조회 수 |
---|---|---|---|---|---|
757 | Develop | [node.js] nodejs 기본 설치 | hooni | 2013.04.23 | 26320 |
756 | Develop | [ios] 구분자로 문자열 자르기 (split) | hooni | 2013.04.23 | 26313 |
755 | Develop |
[python] DJI Tello 드론 코딩 (프로그래밍)
58 ![]() |
hooni | 2018.03.04 | 26005 |
754 | Develop |
GCM 사용하기 3 (JSP로 GCM 푸시 서버 만들기)
4 ![]() |
hooni | 2013.07.06 | 25415 |
753 | Develop |
[c#] 웹문서 소스(html) 긁어오기
![]() |
hooni | 2013.04.23 | 24561 |
752 | Develop |
[c++] MD5 구현 소스.. 퍼움..
![]() |
hooni | 2013.04.23 | 24136 |
751 | Develop |
[ios] 아이폰 개발 총정리..
![]() |
hooni | 2013.04.23 | 23908 |
750 | Develop |
[pdf] GPS의 동작 원리 ㅎㅎ
![]() |
hooni | 2013.04.23 | 23903 |
749 | Develop |
[c] 다중연결 서버 만들기 #4 - thread 사용
![]() |
hooni | 2013.04.23 | 23747 |
748 | Develop |
[c#] 비동기 통신 샘플 코드 ㅎㅎ
![]() |
hooni | 2013.04.23 | 23686 |
747 | Develop |
GCM 사용하기 2 (단말에 GCM 구현하기)
![]() |
hooni | 2013.07.06 | 23404 |
746 | Develop | [ios] UIColor 지정에서 RGB define ㅎㅎ | hooni | 2013.04.23 | 22964 |