CSF periodically blocking external SMTP connection

[workhorse]

CSF periodically blocks an external SMTP server. I have to restart CSF and it will work again for a while. Simply restarting CSF is sufficient, I do not need to modify any configs.

Details:

1. I have SMTP_BLOCK disabled.
2. I am using an external SMTP server
3. I've whitelisted the IPs of that server in csf.allow.
4. It's similar to the topic "SMTP_ALLOWUSER doesn't work intermittently, must restart for" , but that poster had SMTP_BLOCK enabled. (I wasn't allowed to post the link, sorry)

[paul_mcdonald]

Hello ... I'm experiencing the same issue as you describe. Did you ever find a resolution? If so, do you mind sharing what it was?


Thank you!

[paul_mcdonald]

Does anyone have a suggestion here? Only Enabling, then Disabling clears this up for me.

[UWH-David]

How does the log file look? It could be hitting it with too many connections, too many invalid passwords, etc.

[scotw]

Be sure in and out ports for the smtp service are allowed and correct. I had similar issue with virtual servers sometimes seeing the host and sometimes not. Restarting CSF always fixed it. But restarting the virtual server after restarting CSF caused it to be blocked again. Think during CFS restart, the port/connection is opened and allowed. And once CSF was completely loaded, the port/service was assumed to be existing and thus continued to be allowed. Betting if you stop/restart the service after restarting CSF, the port will be blocked again.