Hai,
I am trying to create a mailserver in centos7.
My ip got blacklisted and now i cannot send any messages to gmail etc.
The maillog is showing as follows.
" Our system has detected that this message is suspicious due to the very low reputation of the sending IP address. To protect our users from spam, mail sent from your IP address has been temporarily rate limited. Please visit https://support.google.com/mail/answer/188131 for more information.gsmtp (in reply to end of DATA command)"
I can also see my ip got blacklisted when checked using mxtoolbox.
How to solve this issue?
How to whitelist my ip so that i can send mails again???

Who's your ISP? Where did you acquire your IP address? Is it a hosted server (ex. AWS, some VPS).

Yes its a hosted server, hosted with digitalocean. Also till yesterday i could sent mails using my webmailclient roundcube but cannot receive any mails. But now i am facing a problem as mentioned above.

How long have you been using your IP address? Since DigitalOcean is a hosting provider, most likely the IP address you are using was used before. When was the last time you used this IP when sending mail?

Why did you get blacklisted?
By who?

Some blacklists allow applying for delisting - lots don't.

There is likely no easy fix.

It also helps if the IP of your mail server reverses "properly", for example to www.yourdomain.com or mail.yourdomain.com rather than the usual "generic" reverse that providers usually have.

If you've made it on to a blacklist then, as has been said above, your main hope is that the blacklists have a removal option.

You could also pay for an outbound e-mail service, in the past I've worked for companies that used https://www.fusemail.com/ to spam/virus scan and relay their outbound mail. Many of these services are generally "trusted" by many e-mail providers.

It has become increasingly difficult to run your own mail server because of these often unjustified blockings. A few options:

Don't install your mail server manually. Use VirtualMin. It is FOSS. It provides an excellent interface to managing your mail server. I have been configuring my mail servers manually so I know what I am talking about. I don't feel a whimpy using VirtualMin. Complicated issues like SPF records and DKIM are made easy.

One you have VirtualMin, backups and restore become a breeze. You can afford to have another fully configured VPS host somewhere else. In case of problems you can restore your backups to the backup VPS, set the IP to the backup VPS and you are running again. Recommended to have the backup VPS with a different provider.

I have been using external SMTP providers like Mailgun. That is OK, but undelivery rate is 1-2%. Mailgun gets often blacklisted for some time because it is heavily used for sending advertisements. That is legitimate use, but it does not prevent blacklisting now and then. Mailgun themselves will work hard to get them unblacklisted so that burden is off your back.

A paid SMTP service might be a good solution as well. I had to laugh when I looked at TenTenths suggestion for www.fusemail.com. That is one of those websites showing that they "offer everything", but don't specify WHAT they offer. I could not even find out that they offer SMTP service. Not TenTenths fault, but what a terrible web site.

jlinkels

Laugh all you want

I mentioned them from experience, we used them to deliver millions of e-mails (I'm not exaggerating, one of our projects had 200,000+ users that had to be regularly mailshotted) with a very low bounce/undeliverable rate.

It also seems to be common for companies that provide multiple (expensive!) services to have that style of website.

To the OP:
Have you done this?

Yes, I noticed that. I wonder which type of customer they are targeting at. I can tell you, I quickly click away if I cannot understand what product they are offering.

I mean, if you had not stated that they provide SMTP services, I could not have guessed it.

jlinkels

I am using that ip provided by digital ocean for nearly 2 weeks. i had also visited the link provided in maillog "https://support.google.com/mail/answer/188131" and made a request to unblock my ip address. I cannot use virtualmin, fusemail etc for mail server, since my task is to create a mailserver using postfix, dovecot and roundcube. I should manually create it. I had no issues in sending messages to my gmail accounts till 2 days before. I had sent a lot of mails to my gmail account from the mail server i created for testing purpose. I think thus my port got blocked.

Unless you were sending THOUSANDS of emails per day, it wouldn't have been blocked, especially if your emails were all to the same address. What, exactly, were you sending out, and to how many folks??

Google doesn't blacklist mail servers without good reason. Were you running an open relay? That page they sent you to has several links on it...did you read them? Did you run the postmaster tools they provide? Read the "Bulk sender guidelines"? Read the "Mail forwarding best practices"???? You're asking us what you can do, and the answer is "nothing". Your Linux server and mail system are working...what do you think we'll be able to 'fix', to let you get around a blacklist? If that could be done, every spammer in the world would be doing it.

Read the Google docs, email them, and work with them. If you're a legitimate mailer, shouldn't be a problem.

Occasionally they (and Microsoft) will blacklist entire netblocks. I've had to deal with this before with Microsoft, where my hosting provider had a /24 blocked and unfortunately I had a /28 part of it.

@OP

You can check your IP against known RBLs here

Regards

Personally, I use https://mxtoolbox.com/blacklists.aspx