"SSL23_GET_SERVER_HELLO:unknown protocol" Error Trying to Reach Outlook smtp Server

outlook smtp openssl live-sdk sslv3
jac300 picture jac300 · Mar 12, 2014 · Viewed 10.4k times · Source

I'm trying to send emails from an Outlook account in my iOS application. I'm using Mailcore2 and Outlook's Live-SDK. I am able to receive emails, but get an error when I try to send emails: "a stable connection to the server could not be established".

To investigate the issue, I went into the terminal and tried to connect via SSL:

openssl s_client -crlf -connect smtp-mail.outlook.com:587

The response I got back was:

error:140770FC:SSL routines:SSL23_GET_SERVER_HELLO:unknown  protocol:/SourceCache/OpenSSL098/OpenSSL098-50/src/ssl/s23_clnt.c:607

I don't know exactly what this error means, after a bit of searching I found that a common response to this issue was that the server I am trying to reach may not support a necessary SSL protocol. This site: http://foundeo.com/products/iis-weak-ssl-ciphers/test.cfm allows you to test which SSL protocols are enabled for a particular domain. Using this I found that SSLV2 is disabled and SSLV3 is also disabled.

I not clear on what all this means or what I might need to do to connect to this server. Any help is appreciated.

Answer

AnFi picture AnFi · Mar 12, 2014

SMTP connections to port 587 starts unencrypted. Encryption may be turned out later using STARTTLS command in SMTP session if server supports it.

openssl supports STARTTLS for some protocols including SMTP. It requires -starttls smtp command line options as described in https://stackoverflow.com/a/14645854/2139766

Outlook.com does not seem to support smtps: http://windows.microsoft.com/en-us/windows/outlook/send-receive-from-app

Related questions

SMTP error 554

I'm using MDaemon as out mail server and the last days I get an error "554 Message does not conform to standards" for emails sent from one of the machines. Any idea what may be causing it? Other machines work fine. …

Read More
Unable to send SMTP mails using office365 settings

I am using SMTP mail for sending mail using Laravel. Everything working perfect other than office365 mail settings. Settings I have used is as below: SMTP HOST = smtp.office365.com SMTP PORT = 587 SMTP ENCRYPTION = tls SMTP USER = username(email) SMTP …

Read More
Outlook autocleaning my line breaks and screwing up my email format

I'm sending an email using the dotnet framework. Here is the template that I'm using to create the message: Date of Hire: %HireDate% Annual Salary: %AnnualIncome% Reason for Request: %ReasonForRequest% Name of Voluntary Employee: %FirstName% %LastName% Total Coverage Applied For: %…

Read More