邮件功能支持POP3协议，以及非加密功能

[anonxiaozi]

Pre-checks

• I have searched existing issues and this is not a duplicate.

What problem does this solve?

1. 内网办公环境，目前邮箱服务器还是只支持POP3功能，能否添加POP3的支持；
2. 在使用邮件重置功能时，我发现系统只支持SSL/TLS和STARTTLS，对于有些公司内网邮箱，对安全性考虑不周，还在使用明文25端口，是否能添加这个不安全的支持。

Proposed solution

No response

Willing to contribute?

• I'd be interested in working on this.

[wisdomqin]

Thanks for the feedback! We've addressed the plaintext SMTP relay scenario in the latest version.

About POP3

Clawith's email functionality is outbound only (sending password reset links, invitation emails, notifications, etc.), which uses the SMTP protocol. POP3/IMAP are protocols for receiving email, which is not part of our current use case. If your internal mail server supports SMTP for sending, Clawith can work with it.

Plaintext Port 25 Support (Fixed)

We've updated the SMTP engine to properly support unencrypted internal mail relays:

1. STARTTLS is now auto-negotiated — instead of being forced on ports 25/587, the system checks whether the server actually advertises STARTTLS support. If not, transmission proceeds in plaintext.
2. Authentication is now optional — if the server does not advertise AUTH support (common for IP-whitelisted internal relays), the system skips the login step entirely. This means you can leave the SMTP password field empty for unauthenticated relays.

Configuration for your scenario

In Admin > Platform > System Email Configuration:

• Set SMTP Host to your internal mail server
• Set SMTP Port to 25
• Uncheck "Use SSL/TLS"
• Leave SMTP Username and Password empty (if your relay uses IP whitelisting)
• Click Save, then use "Send Test Email" to verify

Commits: 920a622, ff024c6