My Web-server sends emails to one of our clients who uses Mimecast.com enforced TLS. We Send our emails to our client via gmail.com using secure TLS via our web server. Our SSL certificate is up to date and so is the client we are sending emails to. Delivery is successful but when the client sends us any emails Mimecast turns that message into secure message. Basically you have to log into their secure email web-app and access the emails from there.
This is not convenient for us.
It appears that my TLS is working correctly, but every time they send me an email it uses their secure mail web-app (as if my TLS is not working). MimeCast declined to help. How do I ensure that my email-servers TLS will work with mimecast's email server?
I found that the sort of SSL/TSL that was allowed on my web server was not compatible because it was too new. I updated the webserver to allow older protocols.
Related
I want to send an email to a mailbox on Gmail's servers. But I cannot understand why Google wants to authenticate me, the sender.
I want to act as the sending mail server. So using openssl, I open a TCP connection to smpt.gmail.com. Openssl takes care of the TLS handshake, and I am ready to send a message of the SMTP protocol
openssl s_client -connect smtp.gmail.com:587 -star
ttls smtp
CONNECTED(00000005)
.. Lots of TLS or SSL details ...
---
250 SMTPUTF8
I send the HELO message:
HELO smtp.gmail.com
250-smtp.gmail.com at your service
And I try to send a message:
MAIL FROM: <me#nowhere.com>
530-5.7.0 Authentication Required. Learn more at ...
But Gmail servers responds that I need to be authenticated.
I would understand authenticating with the mail server if I were reading from a mailbox, but I don't get why I need to authenticate to send a message to a mailbox.
I can't find much documentation on the internet regarding this either.
Is there some kind of mechanism where every owner of a mailserver on the planet needs to create a google account just to send emails to a gmail mailbox?
How does the mail servers at Microsoft outlook send messages to Gmail servers?
What am I missing here?
Modern SMTP splits message submission into a separate transaction, distinct from message transport. You are generally required to authenticate with your local MTA (Gmail's if you are sending from Gmail, Outlook if that's where you are sending from, etc) to submit a message, and then the transport network of SMTP proper takes it from there.
There used to be a time when you were able to submit a message to a remote MTA by something called direct injection, but spammers abused this (along with pretty much every other feature of email) to the point where this model was no longer sustainable.
The modern message submission protocol runs on port 587, and generally requires authentication, and thus can obviously only accept submissions from local users for whom the server has identity and authentication information.
The transport protocol, by contrast, runs on the original port number, 25, which is more or less universally firewalled now for residential IP addresses. (Inside an organization, you might still be able to connect to a local mail server on port 25 and perhaps even submit messages without authenticating.)
In addition, regular mail servers on the modern Internet need to maintain a positive reputation. This helps keep the bad apples somewhat isolated, but raises the bar for newcomers and minor independent operators. See e.g. SenderBase for one such reputation system, though the big operators typically have their own proprietary ones which are not available to outsiders.
We are using the SendGrid API to send sensitive email to an Office365 hosted email address. Both services use opportunistic TLS by default, which would in turn make you believe that the email is always going to be encrypted with TLS.
What I'm trying to establish is this enough to assure a client that the TLS email encryption is guaranteed? or do we need to setup enforced TLS in SendGrid? (the con of the later is we then need a mechanism in place to check for emails that have been blocked in the very unlikely event TLS encryption could not be negotiated, which in turn is additional work for us).
Here is some of the information we have been looking at:
https://sendgrid.com/docs/Classroom/Basics/Email_Infrastructure/does_sendgrid_support_end_to_end_tls.html
https://support.office.com/en-us/article/How-Exchange-Online-uses-TLS-to-secure-email-connections-in-Office-365-4cde0cda-3430-4dc0-b489-f2c0736c929f
Thanks
As long as the Office365 server uses opportunistic TLS, and has a valid SSL certificate at all times (preferably issued by a certificate authority, not self signed), then the emails should always get delivered using a safe TLS connection.
If the Office365 server would have an issue at some point accepting TLS encrypted emails, then you should see a deferred event in your SendGrid account, and then the email will be delivered to the server with no encryption.
Cheers!
I'm using Node-RED in IBM's Bluemix. There are nodes to get email in and send email out. However, the email credentials do not seem to be encrypted when sent over the internet. I'm a bit concerned about that. Is there a way to find email receive and email send nodes for Node-RD where they login to the email server using TLS (or SSL)?
If you configure the email nodes to point at SSL/TLS ports then they will connect via a secure channel.
Also I believe that if the mail servers support the STARTTLS command then they will upgrade the connection once connected.
I run a mail server on my web server, it has SMTP authentication enabled and I added my server's IP address to the whitelist, so no password is required to send out emails if they come from within the server. I did this to allow my web applications to use the SMTP service.
My question is can a spammer spoof a packet with my own IP address and bypass the SMTP authentication?
Emails sent from my email server often end up in the recipient's spam folder and I'm trying to figure out why. I send no more than 200 emails per month.
It isn't possible to spoof your address unless the attacker is between you and your server (which is very unlikely - he would have to be an ISP or to be able to overwatch and control your internet traffic). This is because after an attacker sends a connection request to your server, the server sends a packet to you that the attacker needs to have to be able to establish a connection: http://en.wikipedia.org/wiki/TCP_handshake#Connection_establishment
Try to look at the headers of a mail that gets into the spam folder and look for something that says that your servers IP is blacklisted or something like that.
How to send emails in Visual Basic 6 with SSL option enabled?
You could use the webdav protocol to send the email via an IXMLHTTPRequest. An example showing how to do this can be found here.
To send via a server that has an SSL certificate just remember to include the https:// at the beginning of the URL.