1 version=pmwiki-2.2.130 ordered=1 urlencoded=1
2 agent=Mozilla/5.0 (X11; OpenBSD amd64; rv:82.0) Gecko/20100101 Firefox/82.0
10 targets=Openbsd.Mailopenproxy
11 text=(:title Troubleshooting with netcat:)%0a%0anetcat is the swiss-army knife of networking. It is an extremely valuable tool to help diagnose any networking errors. You can and should use it often when working on sysadmin and writing code.%0a%0a!! Debugging SMTP%0a%0aYou can use netcat to test for SMTP errors such as [[openbsd/mailopenproxy|open mail relays]].%0a%0aHere's how to send a simple letter:%0a%0a[@%0a$ nc ircnow.org 25 %0a220 ircnow.org ESMTP OpenSMTPD%0a@]%0a%0aNext, we type HELO followed by our sending domain:%0a%0a[@%0aHELO example.com%0a250 ircnow.org Hello example.com [38.81.163.143], pleased to meet you%0a@]%0a%0aAfterwards, we type our sending mail address:%0a%0a[@%0aMAIL FROM: %3ctest@example.com>%0a250 2.0.0 Ok%0a@]%0a%0aAnd the destination mail address:%0a%0a[@%0aRCPT TO: %3cjrmu@ircnow.org>%0a250 2.1.5 Destination address valid: Recipient ok%0a@]%0a%0aThen we type DATA followed by our email:%0a%0a[@%0aDATA%0a354 Enter mail, end with "." on a line by itself%0aSubject: Alpha Bravo Charlie Delta%0a%0aEcho Foxtrot Golf Hotel%0a@]%0a%0aWe then type . to end the email, then QUIT:%0a%0a[@%0a.%0a250 2.0.0 e57f9a36 Message accepted for delivery%0aQUIT%0a221 2.0.0 Bye%0a@]%0a%0aHere's the complete process:%0a%0a[@%0a$ nc ircnow.org 25 %0a220 ircnow.org ESMTP OpenSMTPD%0aHELO example.com%0a250 ircnow.org Hello example.com [38.81.163.143], pleased to meet you%0aMAIL FROM: %3ctest@example.com>%0a250 2.0.0 Ok%0aRCPT TO: %3cjrmu@ircnow.org>%0a250 2.1.5 Destination address valid: Recipient ok%0aDATA%0a354 Enter mail, end with "." on a line by itself%0aSubject: Alpha Bravo Charlie Delta%0a%0aEcho Foxtrot Golf Hotel%0a.%0a250 2.0.0 e57f9a36 Message accepted for delivery%0aQUIT%0a221 2.0.0 Bye%0a@]
13 title=Troubleshooting with netcat
14 author:1614941973=jrmu
15 diff:1614941973:1614941954:=76c76,79%0a%3c @]%0a\ No newline at end of file%0a---%0a> @]%0a> %0a> %0a> !! Debugging Web Servers%0a\ No newline at end of file%0a
16 host:1614941973=198.251.81.119
17 author:1614941954=jrmu
18 diff:1614941954:1614941931:=
19 host:1614941954=198.251.81.119
20 author:1614941931=jrmu
21 diff:1614941931:1614941931:=1,79d0%0a%3c (:title Troubleshooting with netcat:)%0a%3c %0a%3c netcat is the swiss-army knife of networking. It is an extremely valuable tool to help diagnose any networking errors. You can and should use it often when working on sysadmin and writing code.%0a%3c %0a%3c !! Debugging SMTP%0a%3c %0a%3c You can use netcat to test for SMTP errors such as [[openbsd/mailopenproxy|open mail relays]].%0a%3c %0a%3c Here's how to send a simple letter:%0a%3c %0a%3c [@%0a%3c $ nc ircnow.org 25 %0a%3c 220 ircnow.org ESMTP OpenSMTPD%0a%3c @]%0a%3c %0a%3c Next, we type HELO followed by our sending domain:%0a%3c %0a%3c [@%0a%3c HELO example.com%0a%3c 250 ircnow.org Hello example.com [38.81.163.143], pleased to meet you%0a%3c @]%0a%3c %0a%3c Afterwards, we type our sending mail address:%0a%3c %0a%3c [@%0a%3c MAIL FROM: %3ctest@example.com>%0a%3c 250 2.0.0 Ok%0a%3c @]%0a%3c %0a%3c And the destination mail address:%0a%3c %0a%3c [@%0a%3c RCPT TO: %3cjrmu@ircnow.org>%0a%3c 250 2.1.5 Destination address valid: Recipient ok%0a%3c @]%0a%3c %0a%3c Then we type DATA followed by our email:%0a%3c %0a%3c [@%0a%3c DATA%0a%3c 354 Enter mail, end with "." on a line by itself%0a%3c Subject: Alpha Bravo Charlie Delta%0a%3c %0a%3c Echo Foxtrot Golf Hotel%0a%3c @]%0a%3c %0a%3c We then type . to end the email, then QUIT:%0a%3c %0a%3c [@%0a%3c .%0a%3c 250 2.0.0 e57f9a36 Message accepted for delivery%0a%3c QUIT%0a%3c 221 2.0.0 Bye%0a%3c @]%0a%3c %0a%3c Here's the complete process:%0a%3c %0a%3c [@%0a%3c $ nc ircnow.org 25 %0a%3c 220 ircnow.org ESMTP OpenSMTPD%0a%3c HELO example.com%0a%3c 250 ircnow.org Hello example.com [38.81.163.143], pleased to meet you%0a%3c MAIL FROM: %3ctest@example.com>%0a%3c 250 2.0.0 Ok%0a%3c RCPT TO: %3cjrmu@ircnow.org>%0a%3c 250 2.1.5 Destination address valid: Recipient ok%0a%3c DATA%0a%3c 354 Enter mail, end with "." on a line by itself%0a%3c Subject: Alpha Bravo Charlie Delta%0a%3c %0a%3c Echo Foxtrot Golf Hotel%0a%3c .%0a%3c 250 2.0.0 e57f9a36 Message accepted for delivery%0a%3c QUIT%0a%3c 221 2.0.0 Bye%0a%3c @]%0a%3c %0a%3c %0a%3c !! Debugging Web Servers%0a\ No newline at end of file%0a
22 host:1614941931=198.251.81.119
