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 |
---|---|---|---|---|---|
1173 | System/OS | 해커스랩 깨기.. 후후.. ㅋㅋ | hooni | 2013.04.23 | 18408 |
1172 | Etc | 플라스터(Plaster) 수업 내용 | hooni | 2016.05.24 | 0 |
1171 | Develop | 프로그램 문서 관리 (Doxygen) | hooni | 2013.04.23 | 16383 |
1170 | Develop | 프로그래밍에서 foo, bar 함수의 유래 | hooni | 2013.06.25 | 21237 |
1169 | Develop | 프로그래밍 소스 관련 사이트.. | hooni | 2013.04.23 | 16483 |
1168 | Develop | 페이팔에서 돈 찾기 (Paypal withdraw) | hooni | 2014.02.20 | 10953 |
1167 | Etc | 티스토리 테이블 html,css 구문 | hooni | 2013.11.03 | 15939 |
1166 | System/OS | 콘솔에서 패스워드 걸린 zip 압축하는 명령 | hooni | 2018.03.02 | 923 |
1165 | System/OS | 컴파일러 수업 자료(교재 : 컴파일러 입문) | hooni | 2003.04.23 | 21964 |
1164 | Develop | 캘리포니아 운전면허 족보 | hooni | 2017.06.12 | 720 |
1163 | Etc | 캘리포니아 운전면허 문제 | hooni | 2017.07.22 | 954 |
1162 | Develop | 최근 논문 자료 (2011/01/03, 만현형한테 보낸거..) | hooni | 2013.04.23 | 10366 |