Questions tagged [greylisting]

Greylisting is a technique for fighting spam by initially rejecting emails.

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2answers
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Postfix does not retry after 451 error / greylisting

I have a forwarding server using postfix/dovecot that receives emails from a third party mail client (say gmail) and forwards the emails to the final recipient. I have noticed that when the recipient ...
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1answer
57 views

Is postfix respecting greylist response?

I"m a bit confused about the activity in my mail server logs (addresses and destination redacted for privacy): Nov 1 21:00:03 mail postfix/smtp[745742]: Trusted TLS connection established to mx....
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0answers
30 views

Reloading sqlgrey whitelists?

I inherited admin duties of a postfix server despite having no postfix experience. It's running a service called sqlgrey that is causing all emails from google.com to be greylisted for 30 minutes. I ...
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0answers
15 views

Delivery Status Notifications not being retried

I was checking my ISP's Out of Office reply system and I found that although they sent a message to my server, because my server replied with a 4xx error code, the server did not attempt to re-deliver ...
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1answer
74 views

Is greylisting would effect all domains that serve the same email service?

Is greylisting would effect all domains that serve the same email service? For example: Google is own @gmail.com and @googlemail.com for their email service FastMail have multi domains, you can ...
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1answer
91 views

Qmail SMTP receiver always delays by 66 seconds

I am currently struggling with a problem in my qmail setup, which seems to delay my smtp receiver everytime for 66 seconds. This is for most remote hosts fine, but some seem to reach their timeout and ...
2
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1answer
858 views

default value for auto-whitelist-clients in postgrey dangerous

The postgrey manual sais: --auto-whitelist-clients=N whitelist host after first successful delivery N is the minimal count of mails before a client is ...
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0answers
154 views

Howto configure postfix to correctly handle greylisting when forwarding mail

I have a postfix setup in which I use virtual_alias_maps to forward / alias mails to other addresses. In a specific sample scenario, my server would serve as an MX for the domain mydomain.com and I ...
7
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1answer
9k views

How do I get off Mimecast's greylist?

Emails from our servers sent to Mimecast are being "temporarily rejected" due to greylisting. Mimecast has docs on this; they say that every time they see a unique IP and sender, they greylist the IP ...
4
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1answer
150 views

Is reverse DNS a good method for promoting grey IPs from trusted domains to white?

I'm trying to set up a mail server using OpenBSD, OpenSMTPD, spamd, and pf. The first problem I've encountered is that many large webmail providers - like Gmail - will retry delivery from a different ...
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1answer
3k views

POSTFIX: Limit outbound connections, message count, cummulative size in time window

We are sending quite large amount of email messages to our customers every month with Postfix. Big percentage of them have their email hosted with @example.com. But every month we are struggling to ...
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0answers
95 views

How can I skip greylisting for servers with a valid SPF Record in Postgrey? [duplicate]

I typically do not use grey listing as it doesn't play nice with multiple mx servers, but I do like preventing direct-access attempts to email me (use an MTA, or don't send email). I would like to ...
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1answer
3k views

postgrey whitelist recipients not working

I have installed postgrey and it works fine but I want to exclude some email accounts. So as manual says I added account name into whitelist_recipients then restarted postrgey, postfix but as You can ...
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1answer
1k views

How does postgrey handle changing FQDNs?

Let's say I receive emails from the following clients: mail2.dx300.mail.net mail4.dx121.mail.net mail5.dx121.mail.net Even though these are all from the same service (e.g. LinkedIn or MailChimp), ...
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1answer
2k views

Use greylisting only if SPF fails

I have noticed that more and more people using the DNS based SPF records and I want to enhance my spam filter. I am using SPF and greylisting after each other and my idea would be to use only ...

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