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Questions tagged [starttls]

STARTTLS is the SMTP command to connect to email servers securely over TLS (formerly SSL). Use with an email server tag like [postfix], [exchange], etc.

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sendmail does not issue STARTTLS when acting as a client

I'm having problems relaying to servers that whise mail is routed through mimecast. Connections are being rejected with the message: 553 This route requires encryption (TLS) - https://community.mimecast.com/docs/DOC-1369#553 This makes me think…
Alien Life Form
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Mail server sending to postfix refusing TLS connection with "certificate expired", but it's not

Since April 30, I'm seeing errors like that in my mail log: May 1 02:27:27 afaron postfix/smtpd[2644268]: connect from r137.info.hofer.at[66.117.17.137] May 1 02:27:27 afaron postfix/smtpd[2644268]: SSL_accept error from…
Tobias Leupold
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Cannot get Mutt/Gmail/OAuth2 to work - cannot STARTTLS

I'm trying to get Mutt working with Gmail using OAuth2. I'm using Debian 10 and have compiled Mutt 2.2.1 with --enable-smtp. I've created my tokens. My muttrc contains: set smtp_oauth_refresh_command="~/oauth2.py --quiet --user=my_user@gmail.com…
John Percival
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tls negotiation failed the certificate doesn't match the host

I'm tryin to setup Gmail send-as to send email via my SMTP server over TLS and I get "tls negotiation failed the certificate doesn't match the host" ever since I renewed my lets encrypt cert. Background: I have a server with a dedicated IP sharing…
eng3
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does SSL/TLS STARTLS full encrypt connexion for POP and IMAP

I am configuring POP and IMAP accounts in thunderbird mail client. Here are 2 options: Security: None SSL/TLS STARTLS Authentication method: Normal password Encrypted password Kerberos / GSSAPI NTLM OAuth2 I have 2 mails accounts: One POP and…
Bob5421
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Are SMTPS and IMAPS ports really deprecated?

I've read that STARTTLS command was added and intended to deprecate the SSL ports. But even major mail servers like google still use SSL ports and even don't allow us to use classic ports with STARTTLS. So it seems situation is quite opposite and…
knight_lightning
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How to read an OpenSSL cipher suite list

hMailserver is an open source Window e-mail server. For incoming e-mail it supports STARTTLS with the help of OpenSSL 1.1.1. It allows configuring the cipher suites, the default…
Jeff
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NSS-LDAP not working over TLS: do_open: do_start_tls failed:stat=-1

I'm using NSS-LDAP for authentication. Without TLS, everything works fine. Once I enable TLS (StartTLS) with a self-signed certificate, which I have added to the client, NSS-LDAP won't connect to the LDAP server. systemctl status…
jacobz
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Will msmtp fallback to unencrypted connections if encrypted connections fail?

My ~/.msmtprc config file says to connect to a server on port 25 with tls on and tls_starttls on. Is there a risk that, if the encrypted connection setup fails for some reason, then msmtp will fallback to a plaintext connection, possibly divulging…
a3nm
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Apache and TLS mode - password in plain text in wireshark

My apache.config: LDAPTrustedMode TLS LDAPTrustedGlobalCert CERT_BASE64 /etc/pki/tls/certs/ca.cer AllowOverride None Options None #Order allow,deny #Allow from all AuthType Basic AuthName…
overflowed
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Is TLS necessary for port 25 for MX delivery?

I am in the process of implementing a new Postfix implementation on an existing environment which is extremely old. While doing so I am requiring all clients to connect securely on either 465 or 587 for relay access. The existing postfix…
Michael Moser
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Does anything changes for a client in the API communication after the command STARTTLS is sent and a response received

I'm trying to understand how the command STARTTLS in IMAP works exactly and what becomes different when it's sent. After I've sent the command "STARTTLS" before login process and received the response "OK Begin TLS negotiation now" as a client, does…
Johshi
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Gitlab with OpenLDAP secured with TLS

I have a working, secure OpenLDAP server running at: auth..com I also have a reader account that Gitlab can use: cn=Reader Reader,ou=users,dc=auth,dc=,dc=com Our setup is secured with STARTTLS. Our server will accept no…
Andrew M.
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Outlook 2010 can receive but not send - authentication fails - Thunderbird works

After the mailserver was upgraded from CentOS6 to CentOS 7, Outlook 2010 on Windows 7 can receive email but not send, the error says authentication failed. However Mozilla Thunderbird can receive and send. In the email account SMTP settings 'My…
Nick W
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Postfix 3.4.9 SSL issues -- no shared cipher from servers using TLSv1

Edit 1: I've narrowed it down to TLSv1 that both servers listed below (no others have failed yet) are attempting to use. I'll be contacting their webmasters requesting they stop using an insecure protocol but in the mean time would still like to…
Chris B
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