Ask MetaFilter questions tagged with postfix

Setting policies for email

BrokenEnglish — Thu, 01 Oct 2009 06:23:13 -0800

net.cop filter: What software is available to filter and (optionally) block email between users on the same domain? I'm using Postfix with Google Apps but could be persuaded to use another solution. This is for a school situation, with some very young children who we want to be able to use email but without fully exposing them to the threats of stranger contact (from the wider Internet) or to potential "cyber-bullying" from their peers. So the restrictions might include:

- Kids cannot email each other except when collaborating on a project.
- All email from the Internet to the children will be forwarded to a catch-all account.
- Kids can freely email staff and vice versa.
- Parents on the same domain (we give them an email address for school use) can email staff but not children or other parents.
- Staff can send and receive emails from/to whoever they like including on the Internet.

I will be using Google Apps Education for the front-end, with an internal and outgoing relay using Postfix (but could be persuaded to go to Qmail or another MTA). This means Postfix gets to handle all email sent to/from this domain and that's the point at which I want to be able to apply these policies.

I don't have any sub-domains (e.g. parents.example.com, staff.example.com) so would need something which can work with usernames on one domain and differentiate between the different kind of addresses based on a suffix like "username_parent@example.com" or "username_staff@example.com" unless you can think of a more elegant solution.

Also, have looked at Postini (Google's preferred solution) but it's UKP10,000 per annum and that seems a bit steep to me.

Thanks in advance for any help you can offer.

And pleasepleaseplease, no editorials about how this is wrong or too authoritarian, etc. I really don't want to go there...

Postfix/Altermime vs. Google Apps

doomtop — Fri, 02 May 2008 15:43:04 -0800

E-mail disclaimers: Postfix/Altermime setup works great except when used as an SMTP outbound gateway for Google Apps it strips the HTML version of the disclaimer. So I have finally got Postfix running the way I'd like. I'm using Altermime to automatically attach a disclaimer to the footer of every e-mail sent through it.

Altermime includes a plaintext and an html version of the disclaimer.

Whenever I send an e-mail through Postfix using a mail client (such as Outlook, etc.) the disclaimer works perfectly. It includes the plaintext version and if you view the message in html it includes the html version.

However, when I set up my Google Apps for Domains system to use the Postfix server as the "Outbound Gateway" it somehow causes the html version of the disclaimer to be stripped from the message. So the recipient gets the disclaimer in plaintext view, but if they view it in html there is no disclaimer whatsoever.

I can't seem to figure out where why how this is happening?!@?!

Help me punt email before it wastes postgreys time.

drstein — Sat, 01 Dec 2007 17:50:30 -0800

Spammy spammers sending crap to my mail server are wasting time and resources. I'm using postfix & postgrey (greylisting) on this new server, but.... See the log section here:

Nov 30 19:34:43 heap postfix/smtpd[27141]: NOQUEUE: reject: RCPT from unknown[201.240.117.167]: 450 4.7.1 <7>: Recipient address rejected: Greylisted for 18 seconds (see http://isg.ee.ethz.ch/tools/postgrey...pbp.net.html); from= to=<7> proto=ESMTP helo=
Nov 30 19:34:43 heap postfix/smtpd[27141]: NOQUEUE: reject: RCPT from unknown[201.240.117.167]: 450 4.7.1 <7>: Recipient address rejected: Greylisted for 18 seconds (see http://isg.ee.ethz.ch/tools/postgrey...pbp.net.html); from= to=<7> proto=ESMTP helo=
Nov 30 19:34:43 heap postfix/smtpd[27141]: NOQUEUE: reject: RCPT from unknown[201.240.117.167]: 450 4.7.1 <7>: Recipient address rejected: Greylisted for 18 seconds (see http://isg.ee.ethz.ch/tools/postgrey...pbp.net.html); from= to=<7> proto=ESMTP helo=

--
Postfix is greylisting things for addresses that do not exist on my system. This is the first box that I've used greylisting on. With the previous server, I had Postfix to use a relay_recipient_maps file and that file contained a list of valid email addresses. Anything else was rejected.

While postfix is still rejecting the addresses that are invalid, Postgrey is also getting involved. I'd like to have Postfix just reject the invalid addresses right off the bat before Postgrey gets involved.

In main.cf:
relay_recipient_maps = hash:/etc/postfix/valid_emails

smtpd_recipient_restrictions =
reject_unauth_pipelining,
permit_mynetworks,
permit_sasl_authenticated,
reject_non_fqdn_recipient,
reject_unauth_destination,
check_policy_service inet:127.0.0.1:60000,
check_recipient_access hash:/etc/postfix/recipient_checks,
check_sender_access hash:/etc/postfix/sender_access,
check_client_access hash:/etc/postfix/banned_servers,
permit

--

I really don't want to sign up for the Postfix-users mailing list just to ask one question, and I have already searched Google for this issue to no avail.

Anybody have Postfix-foo that can help me? I believe it might be a matter of re-ordering some of the content checks, but I'm not too sure.
__________________

Mobile users can't send mail through Postfix on my XServe.

odinsdream — Tue, 02 Oct 2007 15:33:48 -0800

XServe Postfix: How can I disable hostname verification so that mobile users can send mail successfully through my server? One of our mail users cannot send messages through our server from her BlackJack phone. Checking the SMTP logs, I see lots of this:

Oct 2 18:15:11 rammserve postfix/smtpd[12253]: warning: 32.161.215.131: hostname mobile-032-161-215-131.mycingular.net verification failed: Host not found

Googling indicates that this is because the hostname has no PTR record. Nothing I can do about that, so I'm looking to disable this check. It's apparently due to the reject_unknown_client_hostname configuration directive, and/or something in smtpd_helo_restrictions.

However, I can't find where any of this stuff is enabled on the server. It's a default configuration XServe. I've looked over the output from postconf -d, but can't find anything that's causing this warning. Where else should I look? Is this even the problem? If not, what else?

How Can I Redirect Queued Mail in Postfix?

ursus_comiter — Fri, 13 Jul 2007 15:04:08 -0800

Can I redirect a queued message in postfix? Ack. A user had forwarding set up to an exchange server that won't talk to the lowly likes of my postfix based mailserver. I've cleaned up their .forward file so that new messages are routed properly, but now there are 160 messages sitting in the queue that still want to go to the exchange server.

The folks running the server don't seem to be very forthcoming about getting things to work on their side, so I'm trying to figure out if there's something I can do to drain the queue into the user's local account.

Throwing the messages back into the queue just results in another attempt and timeout on the exchange server. If I could edit the queued messages in the /var/spool/postfix/deferred directory to change their destination, I should be able to get this cleaned up. However, queued messages aren't in plaintext.

Googling around hasn't shown me anyone dealing with anything similar.

Ultimately, I can use strings to grab content, but that's only a last resort solution for some of the messages if the user can give me specific things to look for for critical messages. I'm not going to do that with all 160 messages though.

Any ideas? Something that can be automated would be ideal.

Thanks!

Help me set up Postfix, please.

odinsdream — Wed, 24 Jan 2007 12:44:02 -0800

Postfix Mail Server Setup: Help me cut through the cruft. I'm attempting to set up a mail server using Postfix and Courier. I'd like to avoid having to learn every single detail about Postfix in order to configure it.

I've worked with several HowTos, but all of them conflict with eachother as far as where mail is stored, how virtual users are set up, and so on. None of the HowTos include all of what I'm interested in.

What I'd like to have:

Basic mail server with virtual users and one domain. The domain could be virtual if it makes things easier, or not. This is one of many conflicts between howtos.
Able to use some kind of web control panel to add/edit users and quotas once initial configuration is finished. This is where almost all of the HowTos don't work - they all end with "And now, all you have to do is edit these complex text files to do even the simplest things! Isn't this clever? Here are some perl scripts!" PHPMyAdmin to edit the databases where users are stored does not count.

My question: Why isn't there a simple-to-install package for Postfix that's mostly set up as above? Is the above somehow uncommon? Why is everyone forced to come up with "Well, this worked for me, YMMV, here's my main.cf" in their HowTos?

Is there an easy-to-install Postfix package? Perhaps a pre-configured dedicated distro?

If it helps, I'm using Ubuntu.

thunderbird and gmail.

craniac — Tue, 27 Sep 2005 11:23:16 -0800

I need a little help with Thunderbird/OSX/Gmail. Specifically, I can't get T-bird to work with Gmail's smtp server. Using these instructions from gmail for configuring netscape, I've got the outgoing mail server set up using port 587, etc. but keep getting the error:

blah blah can't connect to server %S.

I have deleted the outgoing server accounts, replaced them, and tried other ports as well. I have selected TLS rather than SSL, and have tried SSL as well. Postfix is enabled on my pre-tiger machine, and using localhost doesn't work either. Is this a case of corrupted preferences, or is something else wacky going on?

Which mailing list manager should I use?

evariste — Mon, 12 Sep 2005 17:34:16 -0800

Best mailing list manager? I'm running Postfix and Dovecot on a Debian Sarge box. It's for a customer with an approximately 1000-person almost-daily email alert list. They have to pay a lot of money to get on the list, so it shouldn't be possible for some random person to subscribe. It should have a nice web management interface for my customer to do maintenance and pruning, but doesn't have to. It should also have a good security track record, and preferably be F/OSS. It would be nice if it had some kind of intelligent heuristic for removing bad (bouncy) email addresses from future mailings.

Which mailing list manager should I use? ezmlm? majordomo? Something else? Are there questions I should be asking about it that I'm not thinking of? I've never been responsible for someone's mailing list before.

Open source e-mail scalability

id — Fri, 26 Aug 2005 18:38:21 -0800

I am responsible for setting up and maintaining a mail server for small web-hosting type business. We currently host about 75 domains, around 100 mailboxes and due to the efforts of our sales team, we are wanting to get ready for some great increases in those numbers. I am worried about my current configuration and ease of administration. More importantly (well, at least to the customers) is email deliverability -- it seems that messages delivered to some big players are being marked as SPAM or disappearing altogether. I am asking for insight and advice on 1) if my current choice of software/configuration is a good match for this situation and 2) if there any additional measures I might take to ensure email deliverability? Here is an overview of our current setup:

* We lease servers at ev1servers.net.
* The servers are running RHEL ES3.
* We chose to use Postfix and have it configured to support virtual users and domains mapped in MySQL tables. The reference I used to configure this setup is located here. We initially chose Postfix over qmail because it was open and over sendmail because the config files are actually readable.
* I have added in SQLGrey grey-listing for Postfix to provide a simple level of SPAM detection for our users. We are not wanting to deal with the customer service and higher box loads of mail scanning at this time. We might choose to use a 3rd party vendor to do this as needed.
* Messages are delivered locally via maildrop in maildir format.
* Courier IMAP is running to support both IMAP and POP access to the mailboxes.
* Postfix Admin was setup for easy mailbox administration.

For deliverabilty, I have/am taking the following steps:

* I have verified that our reverse IP records are correct
* I have created SPF records for all of the domains
* I have verified that our server is not listed in any blacklists (great scanner at dnsstuff.com)
* I have started to install DomainKeys for Postfix

In doing all of that, I have found that our IP is listed in the BlarsBL. Do I need to be concerned about this rogue list? The IP was there before I even began to setup the box.

I have not yet been able to get DomainKeys to work with Postfix. It was during my configuration attempts that I started to question this setup and wondered if this was the best setup for our situation.. this inquiry has lead to this posting.

In a perfect world, I would have an email server that

* is easy to administer,
* supports automated mailbox setup/removal (currently I can just insert rows into my tables and the mailbox setup is done)
* supports current technologies, like grey-listing, DomainKeys, etc
* is secure
* makes the best use of system resources -- I want to get the "best bang for the buck"

So what do you think? Should I stick with this setup and life will be grand? I am open to something new AND even taking the time to learn a new setup. If I do need to switch to something different, my only concern would be the ability to migrate existing mailboxes and messages over to the new setup.

Are there any other technologies or configurations that I need to implement to support the best deliverabilty rates?

[question posted for a 'friend']

How do I set up a Linux server to receive and store email?

cillit bang — Fri, 04 Feb 2005 18:18:06 -0800

How do I set up a Linux server to receive and store email? (+) I have root access to a server and I want to receive email for my domain and access it via IMAP. This seems obvious enough but every tutorial I've come across assumes you have at least part of it already working and is about changing part of your setup.

I know how email travels through the network fine, but within Linux I am at a loss as to exactly what each piece of software does and how they talk to each other and so forth. And before that, currently mail just bounces. I can't even find the switch in Postfix to turn on receiving mail.

This is on Redhat 7.3. Even getting the thing to forward mail would be nice. Thanks.

PostFix Mail

jackofsaxons — Wed, 29 Dec 2004 10:14:02 -0800

PostFix: I've done the typical searching around on Google, and I'm not having much luck, I'm setting up a mail server using PostFix, with Courier-Pop, procmail and Spamassassin, and my mail isn't being delivered into $HOME/Maildir. Instead it's going to /var/mail/spool. I'm running Debian Woody and the latest version of everything else. I've double checked every config file I can find but there's something I'm missing...

Postfix Fix?

mecran01 — Mon, 02 Feb 2004 10:50:46 -0800

I installed OS X 10.3.2 from scratch on my Imac and it works great. Then I enabled Postfix using "postfix enabler" and I was receiving email and it was a glorious moment.

However, during my attempts to enable procmail, I broke something and even reverting to the backed up postfix config files won't fix it, nor will re-running postfix enabler.

Can I restore Postfix to its pristine state without reinstalling 10.3, or can I reinstall 10.3 and retain all of the stuff I installed using Fink?

Many thanks. I would ask this question on a newsgroup, but that postfix crew are a bunch of meanies. In retrospect, this question is probably a little too narrow for this forum.