The server configuration of email, including POP3, SMTP, IMAP, and popular server software packages that control email.

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Why an empty MAIL FROM address can sent out email?

We are using Smarter Mail system. Recently, we found that hacker had hacked some user accounts and sent out lots of spams. We have firewall to ratelimit the sender, but for the following email, the ...
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3answers
6k views

Send spam mail to a special folder using postfix

I have a postfix server running amavis and SpamAssassin to help filter spam. Messages that are detected as spam look like this when delivered into the user's Maildir: From tom@tom-mint Fri Mar 15 ...
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3answers
6k views

Sending email from my server

So, I'd like to send email from my server. I installed mailx apt-get install mailx But a command like mail -s "Hello world" me@gmail.com Is actually giving an error in /var/spool/mail/ which ...
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3answers
388 views

Is SPF enough to make sure emails get delivered to inbox?

So I just succesfully set up postfix + dovecot. is SPF enough to make sure emails get delivered to my website's users? I don't want my emails to end up in their spam box.
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4answers
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Do i need to open 25 port to send emails with the php mail function?

I have a Linux web app. Do I need to open port 25 to only send emails using the PHP mail function? If I have to open port 25, how can I disable receiving emails? Edit: I am asking because I ...
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3answers
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Does anyone have real-life examples of e-mail being intercepted?

As anyone will tell you, e-mail is not secure. It travels around the Internet in plain text and we should not use it for sending passwords and other sensitive details. For years I've been designing ...
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4answers
3k views

How to send 100,000 emails weekly and avoid being considered spammer

I have a mailing list with 100,000 email addresses, and I have to send it an email weekly. What application/program/webapp/script/etc do I have to use to send 100,000 emails weekly and avoid being ...
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2answers
910 views

Parse undelivered mail headers (bounced mail)

What is the best way to parse the headers of bounced (undeliverable) email that is sent back to my server and determine whether it is a soft or hard bounce? I only send opt-in emails to my users, but ...
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1answer
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Does postfix reject spoofed senders?

Is there a reliable way to reject incoming mails with a spoofed e-mail address? What kind of checks does postfix run normally on incoming mails? does postfix check the reverse dns by default? does ...
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1answer
180 views

Is an MX record needed?

We have a testing server with its own domain name. We don't want any email to be sent from this domain. We don't want any email to be received on this domain. Is it ok to remove the MX record ...
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5answers
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Demanding your clients to change extensions from .zip to .txt for mail attachments

A company we are working with has a few ridiculous security measures. One of them goes like this: You cannot e-mail us .zip files. If you want to transmit a .zip file, rename it to .txt. IMHO, ...
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6answers
2k views

Prevent outgoing spam

What are some ways to prevent spam from leaving your servers should a hosting account get compromised? Have a bunch of clients on a server with cpanel but wondering if there was a way to just ...
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2answers
19k views

Why is my email server in AT&T's blacklist?

I just got this bounce message: <████████@att.net>: host scc-mailrelay.att.net[204.127.208.75] said: 521-88.208.246.34 blocked by sbc:blacklist.mailrelay.att.net. 521 DNSRBL: Blocked ...
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5answers
4k views

Does it really matter what your server's hostname is?

I'm kind of hesitating if I should use a subdomain or just a plain word as hostname. E.g. my domain name is domain.com and my server's hostname ip1.domain.com. This might be a strange question but ...
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2answers
395 views

What is push email?

Looking for a true technical explanation on this.
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4answers
1k views

ptr for a subdomain

I’m feeling lost in DNS; please help me get back on track. I’ve got a domain. Let’s call it example.com. And I can add DNS entries for subdomains of type A and CNAME. I have another server which I ...
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1answer
3k views

Full status information in Nagios email notification?

I have set up Nagios to monitor my servers and I have written a few custion checks. When I get a notification email, I only get the first line of the status information and I have to use the web ...
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3answers
470 views

How to get Postfix statistics of second instance?

I have a quick question. I have two instances of Postfix running on an Ubuntu server and I want to write some scripts to email our server admin Postfix statistics (queue count, sent, etc). How would I ...
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2answers
4k views

Sending mail from command line if body not empty

I'd like to write a simple script that alerts me if a log changes. For this I'm using grep to find the lines I'm interested in. Right now it works like this: grep line /var/log/file | mail -s Log ...
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3answers
7k views

Linux: Send email to another address instead of /var/spool/mail/root

I manage a micro linux server on Amazon EC2. Occasionally I get email sent to the root account and if I'm logged in, I'll get the notice: You have new mail in /var/spool/mail/root How do I get ...
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3answers
95 views

What to do if one doesn't want to receive email bounces?

Background—the standards RFC 5321 §4.5.5 states: All other types of messages (i.e., any message which is not required by a Standards-Track RFC to have a null reverse-path) SHOULD be sent with ...
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2answers
561 views

Perfect Forward Secrecy (PFS) for mail servers

Perfect Forward Secrecy is an important enhancement to SSL/TLS communications, helping prevent captured SSL traffic from being decrypted even if the attacker has the private key. It's easy enough to ...
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4answers
4k views

Can an e-mail's headers tell you if it has an attachment?

I'm trying to filter emails that have attachments, but in the system I'm using I only have access to the headers (for filtering). Is there a consistent way of determining if an e-mail contains ...
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2answers
3k views

Postfix: How to accept email from a specific non-existing domain?

We need to accept email from a server that sends out using a non-existing domain. That server is not under my control. In my main.cf I have smtpd_client_restrictions = permit_mynetworks, ...
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2answers
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Does the presence of a Content-ID header in an email MIME mean that the attachment must be embedded?

Two different third-party email products we have are reacting differently to the presence of a content-id header in the MIME source of an email. This is resulting in an inconsistent user experience ...
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1answer
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Exchange 2010: Log in to another user's mailbox with an admin user that does not have a mailbox

We have Exchange 2010 users that are part of the following Exchange groups: Organization Management Server Management However, these accounts do not have Exchange mailboxes. We could log in to ECP ...
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2answers
299 views

Can spammers extract valid email addresses from my mail server?

I have a 12 letter and number email address. The email address have never been used on the web or have been used to send email to others, yet I get spam on it. This has happened to me on both Linux ...
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2answers
2k views

Custom headers in Email lost?

I have some questions about custom mail headers Does anybody know of any mailserver which deletes proprietary/custom headers when being transmitted to its destination? Is there a header you can set ...
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4answers
2k views

Free calendar server? [closed]

I am looking for free calendar server who can authenticate to LDAP server. I want our users to use thunderbird lightning with calendar server. We have mail server with devcot and squirlmail for ...
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7answers
2k views

Receive email alerts from Linux file server

GOAL: Get a text file on my file server into my gmail inbox. The file server is running Ubuntu Server 8.04 I currently SSH into it from time to time and to check logs, SMART stats for hard drives, ...
5
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1answer
513 views

Does anyone recognize this e-mail sniffer or malware using ROT13 encoding?

I have a private website that every week sends e-mails with two different http links to a group of around 30 people. When a link is clicked, the answer is registered in a database. Starting last week, ...
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1answer
233 views

Does the MTA (Postfix, Exim, etc.) get installed seperate from the mail server

I'm new to mail servers and still trying to understand all the components. What I read is that there are many MTAs, but the 4 common ones are qmail, Postfix, Sendmail, and Exim. I also found this ...
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Hotmail Sender ID always fails with “temperror” regardless of SPF

When we send mail to Hotmail servers, they do not recognize our Sender ID. In the receiving mail source, it reads Authentication-Results: hotmail.com; sender-id=temperror ... when it should say pass ...
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2answers
12k views

How to setup a email address for a domain on Amazon EC2?

I am not used to cloud hosting. Previously I would just setup an email account through cPanel, but since this is not available how would I go about doing this on a Amazon EC2 account? I am assuming I ...
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6answers
8k views

Emails going to Junk for Hotmail recipients [duplicate]

We send daily mass emails to our customers (~30,000+ emails per day). We have problems with Hotmail users receiving our emails. Sometimes the email goes to the Junk folder, but often it will got to ...
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6answers
4k views

How might I stop BACKSCATTER using qmail?

I have a Linux box acting as Virtual Host for domain hosting. It runs CentOS and Parallels Plesk 9.x. Regardless of the following, the SPAM keeps flowing in at 1-3 / second. An explanation of the ...
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12answers
8k views

Personal email archive alternative to PST files

If you aren't willing or able to prevent users from keeping old emails "forever", what solution do you have? Exchange 2007 allows pretty massive mailboxes, but lots of people still recommend against ...
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4answers
1k views

Reject incoming emails that use your own domain as sender

It would be nice to reject incoming emails which use one of my virtual domains as sender address while not being a legitimate user of mine. I know that I can reject incoming emails which use an ...
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1answer
3k views

Turn of amavisd notifications about UNCHECKED content to postmaster

How do I turn off "UNCHECKED contents in mail FROM" mails send by amavis to the postmaster of the domain every time a user sends an encrypted mail. The setup is a Debian 7 with postfix and amavisd.
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1answer
924 views

SPF vs. DKIM - The exact use cases and differences

I'm sorry for the vague title. I don't fully understand why SPF and DKIM should be used together. First: SPF can pass where it should fail if the sender or DNS is "spoofed" and it can fail where it ...
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1answer
740 views

How can I proactively detect compromised Exchange 2010 accounts?

We have had issues with compromised Exchange accounts sending out malicious e-mails via SMTP and OWA. It seems that many of these accounts were compromised via incoming phishing attempts. We are ...
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1answer
4k views

modify the recipient address of an email on the file in the postfix queue

I have a few emails in my mailq which are bounced for a good reason, the email address is wrong. I was wondering if it is possible to modify the address of the recipient on the fly. I can see the ...
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1answer
518 views

Postfix SMTP sends to localhost, ignores MX records set to Google Apps

I have the MX records for zaltin.com set to the Google Apps domains (aspmx.l.google.com etc.). If an email is sent to kerrick@zaltin.com from most places, it goes to my Google Apps account. However, ...
5
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1answer
481 views

Adding QR Codes to Exclaimer

We are running a piece of software called Exclaimer which sets a standard template for email signatures and grabs some details from Active directory, like Contact numbers and title. I need to add a ...
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5answers
14k views

Is there a way to use the Autodiscover feature without Exchange?

The autodiscover method used by Exchange looks great. However I do not have Exchange. It looks like when setting up a mail account the device/mail client looks for a autodiscover.xml file. Is there ...
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4answers
8k views

What exactly is a X-YMailISG header?

Finally ... our emails are being seen by Yahoo! not as junk anymore. Hurray! However I notice that the Yahoo! receiving MTA adds in a X-YMailISG header. It's very large ... 2**10 bits? Now that ...
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3answers
7k views

Configuring php mail() per domain

I have about 6 sites on my dedicated server (running centos5), and all emails sent using php's mail function are sent by nobody@servername.hostname.com e.g. "Received: from nobody by ...
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4answers
5k views

Low disk space email alert

Very simply I am trying to trigger an email alert from a Windows 2003 server to tell me when the disk space is low. Has anyone had experience with setting this up? Thank you.
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2answers
4k views

Disabling Specific Options in Outlook 2010 through Group Policy?

Alright, all research thus far has failed me, this must be a somewhat obscure problem. I think I am close but I need an answer as to whether or not what I am trying to do is possible so I don't waste ...
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1answer
57 views

MS Exchange — running code against outbound email

I would like to know if using MS Exchange there is a way to run code against outbound emails. The code would need to trigger on emails sent to a specific domain, connect to a database, check for an ...