timeout error with usocket on common lisp - sockets

Question

I’m having trouble with cl-smtp:send-email which seems to stem from a timeout error when calling usocket:socket-connect.
Here is what I am trying to do:
(cl-smtp:send-email "outgoing.mit.edu" "m_klein#mit.edu"
(list "m_klein#mit.edu") "s1" "m1”)
This seems to be the call where the failure occurs (according to the backtrace):
(usocket:socket-connect "outgoing.mit.edu" 25
:protocol :stream
:element-type '(unsigned-byte 8)
:timeout nil
:deadline nil
:nodelay nil
:local-host nil
:local-port nil)
Here is the error:
Error: Error #<USOCKET:TIMEOUT-ERROR #x302001E5FDED>
While executing: USOCKET::RAISE-ERROR-FROM-ID, in process Listener(475).
The odd thing is that the same function call has worked on other machines, but not on my current mac laptop or the cloud-based mac I’ve also been using.
I am running Clozure Common Lisp 1.11.1 on a MacBook Pro on OS 10.13.3
Here are snapshots of the backtrace FYI: https://imgur.com/a/e2xcf
Any ideas? Any help would be greatly appreciated.

Answer 1

Since you are using an external server, first you need to check, correctness of the address (connect using telnet), port and maybe you need an authentication.
Since you are using cl-smtp, first I recommend you to test how it works, for that the easy way of testing smptp is using mailcatcher inside a docker container:
docker run -d -p 1080:1080 -p 1025:1025 --name mailcatcher schickling/mailcatcher
docker ps | grep mailcatcher
6fb056fceb6b schickling/mailcatcher "mailcatcher -f --ip…" 9 months ago Up 18 minutes 0.0.0.0:1025->1025/tcp, 0.0.0.0:1080->1080/tcp mailcatcher
Then you can access to the ourtgoing mail in a web browser localhost:1080, and send mail to localhost:1025
For testing the SMTP, server I recommend to use telnet:
telnet
telnet> o localhost 1025
Trying ::1...
Connected to localhost.
Escape character is '^]'.
220 EventMachine SMTP Server
EHLO localhost
250-Ok EventMachine SMTP Server
250-NO-SOLICITING
250 SIZE 20000000
there is a great article on that here
When you are sure that, you get the requirements try with lisp:
CL-USER> (cl-smtp:send-email "127.0.0.1" "antonio.querol#example.com" "pedro.lopez#example.com" "Say Hello" "Hello World"
:port 1025)
("Ok")