Although I have created the rule, SMTP is blocked

pedritorico · April 11

I have created a NAT 1:1 rule, see pictures.
I have created a security policy, see pictures.
Despite this, I do not get SMTP allowed. I only want certain IP addresses to be allowed access. These are from Office 365.
Please help I can't get any further.

pedritorico · April 12

Hi everyone,

@PeterUK the nat rule was wrong, I have changed to any and now it works. Thank you very much.

But do I need also a outgoing rule?

regards

PeterUK · April 12

By default their is a rule to send any traffic outgoing I guess you have a Mail server then with a trusted IP to send mail.

PeterUK · April 11

Are you sure you need inbound connection and not outbound?

Some ISP block port 25

looking at your NAT rule source IP should be any it makes no sense to be WAN1_IP that for external

smb_corp_user · April 12

https://community.zyxel.com/en/discussion/22108/although-i-have-created-the-rule-smtp-is-blocked

Are you sure that TCP port 25 is allowed for Office 365 in your case? The normal port to use is 587 (STARTTLS) for modern and current subscriptions, unless you are using Exchange.

TCP Port 25 is insecure and exposed, just like HTTP without SSL.

pedritorico · April 12

Hi everyone,

@PeterUK the nat rule was wrong, I have changed to any and now it works. Thank you very much.

But do I need also a outgoing rule?

regards

PeterUK · April 12

By default their is a rule to send any traffic outgoing I guess you have a Mail server then with a trusted IP to send mail.

Although I have created the rule, SMTP is blocked

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