For the mail server to work properly, it is important to have a properly configured DNS zone. We have already touched on some aspects related to the DNS system, today we will dwell on this issue in more detail. DNS setup zones refers to the preparatory operations before deploying the mail server and the system performance directly depends on it Email.
Wrong settings can cause mail to be undeliverable to your mail server or recipient servers to reject your mail. Indeed, if your zone records do not contain information about the mail server, where should mail be sent? To the grandfather's village? You can, of course, ask your provider to configure the DNS zone, but it's better to do it yourself.
What do we need? A dedicated IP address (let's say 11.22.33.44) that you must obtain from your ISP. Domain name (for example example.com), it can be registered with any registrar or their partner. When registering with a partner, check whether it provides access to DNS zone management, otherwise you will have to spend additional time, nerves and money transferring the domain to the registrar.
If you already have a domain and, most likely, a site is functioning on it, check whether it is possible to manage the DNS zone from the hosting provider's panel, otherwise it is better to transfer the domain to the registrar, for this contact the provider's support.
So, we have a domain. What records does its DNS zone contain? First, it is a SOA record - a description of the zone. We will not analyze all the entries in detail, this is beyond the scope of our article, but it is necessary to have a general idea of them. There should also be two NS records pointing to nameservers ( DNS servers) serving this domain, these will be the registrar's servers or the hosting provider.
The first entry you need to add will be the A entry, or name entry. It should point to the IP address of your server if you decide to serve all requests to the domain on your own or to the IP address of the hosting provider if you decide to host your site. When hosting a site, the domain is usually delegated to its DNS servers (corresponding NS records are registered) and an A record will be made automatically when the domain is parked.
This option is most common, but if necessary, you can always create an A record yourself. This entry has the form
example.com. IN A 22.11.33.44
In our example, 22.11.33.44 is the address of our hosting provider, where the site is located. Pay attention to the dot at the end of the name, this indicates that the name is absolute, in the absence of a dot the name is considered relative and is added to it Domain name from SOA. You can check the entry with the command nslookup.
For the mail server to work, you need to create an MX record, which should point to our mail server. Let's create an entry for this:
example.com. IN MX 10 mail.example.com.
You can also just write:
example.com. IN MX 10 mail
To this name (without a dot at the end) example.com will be added automatically. The number 10 determines the priority of the server, the lower it is, the higher the priority. By the way, the DNS zone may already contain an MX record of the form:
example.com. IN MX 0 example.com.
Usually this entry is automatically created by the hosting provider when hosting the site, it must be removed.
Now let's create an A record for mail.example.com
Mail.example.com. IN A 11.22.33.44
Now all mail for the example.com domain will be directed to the mail host with the address 11.22.33.44, i.e. your mail server, while the site example.com will continue to work on the provider's server at 22.11.33.44.
The question may arise, why can't you immediately specify the IP address of the mail server in the MX record? In principle, it is possible, some do, but it does not comply with the DNS specifications.
You can also make aliases for the mail server like pop.example.ru And smtp.example.ru. Why is it necessary? This will allow the client not to depend on the features of your infrastructure, once setting the settings. Let's say that your company has grown and allocated a separate mail server to serve external clients. mail1, all you need to do is change two DNS records, clients will not notice that they are working with a new server. To create aliases, CNAME type records are used:
Pop IN CNAME mail.example.com.
smtp IN CNAME mail.example.com.
At this point, the forward DNS zone setup can be considered complete, the most interesting thing remains - the reverse zone. The reverse zone is managed by the provider that issued you the IP address and you cannot manage it yourself (unless you are the owner of the block of IP addresses). But you must add at least one record to the reverse zone. As we wrote in the last article, many mail servers check PTR records (reverse zone records) for the sending server, and if they are absent or do not match the sender's domain, such a letter will be rejected. So ask your provider to add an entry like this for you:
44.33.22.11.in-addr.arpa. IN PTR mail.example.com.
A bit strange looking, isn't it? Let's analyze the structure of the PTR record in more detail. For reverse name resolution, a special top-level domain in-addr.arpa is used. This is done in order to use the same programming mechanisms for forward and reverse name resolution. The fact is that mnemonic names are written from left to right, and IP addresses are written from right to left. So mail.example.com. means that host mail is in the domain example, which is in the top-level domain com., 11.22.33.44 means that host 44 is in subnet 33, which is part of subnet 22, which belongs to network 11. To maintain a uniform order, PTR records contain the IP address " backwards" completed with a top-level domain in-addr.arpa.
You can also check MX and PTR records with the command nslookup using additional parameter -type=MX or -type=PTR
And of course, you should not forget that any changes in DNS zones do not occur instantly, but within a few hours or even days, necessary for the distribution of changes in the global DNS system. This means that despite the fact that your mail server will start working 2 hours after the changes are made, your partner may not send mail to you for a longer time.
For those who want to try their hand at self installation and setting up a mail server, we will walk through the process step by step installation mail server based windows server Server 2003/2008/ and hMailServer software; go through the stages of organization and setup DNS service within the same server, and adding your mail domain to the server.
The material uses software hMailServer version 5.0-B305.
Download the mail server software from the link:
We launch the downloaded program. The first dialog is the welcome dialog, click Next.
The next step is the license agreement:
Choose the path to install the program:
Select the components to be installed, select all:
Select the built-in database:
Enter the name in the start menu:
We check the entered data and agree:
Set a password for server administration:
After everything is installed, we can start administration, located in the Start Menu. The first thing we will see is the connect dialog. With this program we can connect to any hMailServer. We will connect to localhost, click connect, in the password dialog enter the password that we set during installation.
The first thing we should see is the Wellcome tab, select the Add Domain... option here, enter the name of our domain bestdomain.com and select Save. Our mail domain is active and ready to go. Now you need to add a user, open the Domains tab, then open the bestdomain.com tab, then select the Accounts tab.
Here we can add, remove and edit users. Selecting the Add...
General tab - username, password, mailbox quota and rights are set here.
Auto-reply tab - here you can configure an auto-responder for a specific user.
Forwarding tab - here you can configure mail forwarding for a specific user.
Tab Signature - the signature is set.
Tab External accounts - the ability to collect mail from other servers for a specific user.
Tab Rules - setting all kinds of filters.
Tab Active Directory- if necessary, the ability to work with the corresponding service name.
Tab Advanced - setting the last name and first name of the user, administration of his mail folders.
Aliases domain tab - allows you to configure aliases for a specific domain, the Distribution List domain tab allows you to create mailing lists.
There are other global tabs Rules, settings for global filters, Settings, settings for protocols, logs, anti-spam and anti-virus connection.
Various server maintenance tools.
SMTP ports 25, POP3 110, IMAP 143 must be allowed in the firewall.
When setting up an email client, you must remember that the username for POP3, IMAP, SMTP is set as [email protected].
Start -> Control Panel -> Add or Remove Programs
In the window that opens, select Add / Remove Windows Components should start Windows wizard Component Wizard. There we become the Networking Services item, select Details, mark Domain Name System (DNS), then OK and Next, then you may need a distribution kit with a Windows installation (specifically the i386 folder) and reboot the system.
After installation, we can start configuring DNS:
Start -> Administrative Tools -> DNS
Expand the tree with the name of the computer -> click right click on Forward Lookap Zones -> New Zone
In the wizard that opens, select Next -> Primary Zone -> Next -> Enter the name of the zone bestdomain.com -> Next -> agree with the file name Next -> Do not allow dynamic updates -> Next -> Finish
We create all the necessary domains, the first one is the root domain, the domain name is empty, IP Address 100.100.100.100 -> Add Host. Next, create all the necessary hosts by entering in the field Name values www, ns1, ns2, mail IP Address 100.100.100.100 -> Add Host. At the end, select Finish.
The next step is to edit the settings of our zone, right-click on the name of the created domain and select Properties -> in the dialog that opens, select the Name servers tab -> Delete the automatically created one with the Remove button -> Add two server names ns1 and ns2 with the Add button -> Enter the name server and its IP.
The next tab Start of Authority (SOA) enter all the specified values, after all changes to the domain now and in the future, do not forget to make an Increment for the zone, serial number increases by 1.
The next step is to add MX for mail to work, as well as for creating hosts, right-click New Mail Exchanger (MX).
Leave the domain name blank, enter the DNS name of the mail server and priority 10 and click OK.
DNS is configured and ready to go!
You can work with emails not only through the Yandex.Mail web interface, but also using various email programs installed on your computer.
When using the IMAP protocol, the mail program synchronizes with the server and maintains the folder structure of your mailbox. The letters sent by you through the mail program will be stored not only on the computer, but also on the server, and you will be able to access them from various devices.
Before configuring the mail program, enable the IMAP protocol:
To set up your mail program IMAP protocol you must provide the following information:
Incoming mail
connection protection - SSL;
port - 993 .
connection protection - SSL;
port - 465 .
. en »
Support for the IMAP protocol will be enabled automatically upon first authorization in the mail program.
When using the POP3 protocol, all messages from the folders that you specify in the menu Setting → Email programs, will be saved by the mail program to your computer in the Inbox folder. If necessary, you can set up filters in your mail program to automatically move messages to the correct folders. The emails you send will only be stored on your computer.
Note. When downloading emails from a server using the POP3 protocol, Yandex.Mail automatically saves copies of emails on the server, but you can delete emails manually using the web interface. If you want to delete emails with a mail program, use the IMAP protocol.
Before setting up the mail program, enable the POP3 protocol:
To configure a mail program using the POP3 protocol, you must specify the following data:
Incoming mail
connection protection - SSL;
port - 995 .
mail server address - smtp.yandex.ru;
connection protection - SSL;
port - 465 .
To access the mail server, enter your Yandex username and password (or if you have enabled two-factor authentication). If you are setting up receiving mail from a mailbox of the form " [email protected].en », the login is the part of the address before the "@" sign. If you use , you must specify the full address as a login mailbox.
You can set up receiving emails via POP3 protocol from any folder, including Spam. To do this, open the menu Setting → Email programs and mark the desired folders.
When downloading the contents of the mailbox by mail programs, messages are not marked as read by default. If you want to mark received emails as read, enable the corresponding option.
This step by step guide will help you solve problems related to Yandex.Mail and the mail program.
This step-by-step guide will help you solve problems related to Mail in Connect and your mail program.
Select an issue:
What message did you receive?
Did you manage to login?So the problem was that you didn't accept the terms. They are accepted automatically when you log in to the Yandex.Mail web interface for the first time.
Make sure that the protocol you want to use is enabled in the settings section.
Please make sure that you have correctly\n specified the following server settings in your mail program settings:\n \n \n
If you are using IMAP
mail server address - imap.yandex.ru;
\nconnection protection - SSL;
\nport - 993 .
\nmail server address - smtp.yandex.ru;
\nconnection protection - SSL;
\nport - 465 .
\n\n \n \n \n
If you are using POP3
\n \n \n Incoming mail \n \n
mail server address - pop.yandex.ru;
\nconnection protection - SSL;
\nport - 995 .
\nmail server address - smtp.yandex.ru;
\nconnection protection - SSL;
\nport - 465 .
\n\n \n \n \n\n
For more information on how to check server settings in different mail\n programs, see the section.
\n ")]))">
Make sure that you have accurately specified the following server settings in the mail program settings:
If you are using IMAP
Incoming mail
mail server address - imap.yandex.ru;
connection protection - SSL;
port - 993 .
mail server address - smtp.yandex.ru;
connection protection - SSL;
port - 465 .
If you are using POP3
Incoming mail
mail server address - pop.yandex.ru;
connection protection - SSL;
port - 995 .
mail server address - smtp.yandex.ru;
connection protection - SSL;
port - 465 .
For more information on how to check the server settings in different email programs, see the Encryption of transmitted data section.
If the message "Authentication required" appears, "Sender address rejected: Access denied" or “Send auth command first”, authorization on the Yandex SMTP server is disabled in the mail program settings. Make sure the option is enabled User Authentication(for Outlook Express) or SMTP authentication(for The Bat!).
If you are a member of an organization and the problem is reproduced in all mailboxes of the domain, you need to log in to the web interface for each of them. It will not be possible to do this centrally, because each Mail user must accept the terms on their own.
If a message occurs "Sender address rejected: not owned by auth user", the address from which you are trying to send an email does not match the one under which you are authorized on the SMTP server. Make sure that in the settings of the mail program, the return address is exactly the address from which the login is used in the authorization settings for SMTP.
If you are a member of an organization and the problem is reproduced in all mailboxes of the domain, you need to log in to the web interface for each of them. It will not be possible to do this centrally, because each Mail user must accept the terms on their own.
If a message occurs "Login failure or POP3 disabled", the mail program cannot access the mailbox using the POP3 protocol. Make sure that you have entered the correct password for the mailbox and that access via the POP3 protocol is enabled in the settings section.
If you are a member of an organization and the problem is reproduced in all mailboxes of the domain, you need to log in to the web interface for each of them. It will not be possible to do this centrally, because each Mail user must accept the terms on their own.
If a message occurs "Message rejected under suspicion of SPAM", the content of your message was recognized by Yandex.Mail as spam. To solve the problem, open Yandex.Mail and send any one email as a test. This way you will prove to the system that the letters are not sent by a robot.
Check your computer for viruses with free antivirus programs: CureIt! from Dr.Web and Virus Removal Tool from Kaspersky Lab.If you are using antivirus program, firewall or proxy server, disable them and see if this reproduces the problem.
If you are a member of an organization and the problem is reproduced in all mailboxes of the domain, you need to log in to the web interface for each of them. It will not be possible to do this centrally, because each Mail user must accept the terms on their own.
Read step by step instructions to search for missing letters. Before starting work .
Select an issue:
When you delete emails, they go to the Deleted Items folder and are kept there for 30 days. During this period, you can restore them:
Go to the Deleted folder.
Highlight the letters you want.
Click the Go To Folder button.
If more than a month has passed since they were deleted, you won't be able to restore the messages - they were permanently deleted from the Yandex.Mail servers.
If the letters are not in the folder where they should be, then most likely they ended up in another folder, for example, in Deleted Items or Spam. If you remember the name or address of the sender, part of the text of the letter or the subject - try to search for letters in all folders in your mailbox.
Did you find letters?
You can recover emails:
Navigate to the folder where the emails were found.
Highlight the letters you want.
Click the Go To Folder button.
Select the folder where you want to move the messages from the list - for example, Inbox.
Why Emails Disappear and How to Avoid It
In the Deleted mail folder, 30 days are stored, in the Spam folder - 10 days. After that, they will be permanently deleted from Yandex servers. Why emails can end up in these folders without your knowledge:
Another user has access to your mailbox
Emails can be deleted by a user who has access to your mailbox: you may have forgotten to log out after working on someone else's device. To end a session, click on the menu account link Sign out on all devices. You can also do this on the page - using the link Sign out on all computers.
Letters disappear in the mail program
configure the program using the POP3 protocol
Set up a rule that deletes or moves letters Letters disappear in the mail program
If you use a mail program and delete letters in it, then they disappear on . This happens because your program is configured using the IMAP protocol - while the structure of the mailbox on the service is synchronized with the structure of the mailbox in the program. To delete messages only in the program, but leave them in Yandex.Mail, you can configure the program using the POP3 protocol, but we recommend not to do this: letters may not be synchronized correctly with the server.
Set up a rule that deletes or moves emails Specify reliable ones in Yandex.Passport and link them to your account. Perhaps our security system found your account suspicious and blocked the mailbox. Most often this happens due to the fact that a phone number is not attached to the box or a fictitious name and surname are indicated in the Passport. It usually takes a couple of hours to unlock.
If you delete messages in a mail program, but they are still in their folders on the Yandex.Mail website, then most likely your mail program is configured using the POP3 protocol. Due to the peculiarities of the POP3 protocol, messages in the mail program may not be synchronized correctly with the server. It is recommended to use the IMAP protocol to work with Yandex.Mail. To migrate your email program from POP3 to IMAP, see Switching from POP3 .
If your email program doesn't show sent emails, then most likely your email program is configured with POP3 protocol. Due to the peculiarities of the POP3 protocol, messages in the mail program may not be synchronized correctly with the server. It is recommended to use the IMAP protocol to work with Yandex.Mail. To migrate your email program from POP3 to IMAP, see Switching from POP3 .
If you receive invalid certificate errors when activating SSL encryption in your mail program, make sure that your mail program and operating system configured correctly:
Add a certificate to the list of trusted certificates manually (Windows)
Attention. If you are not sure that you can install the certificate yourself, contact a specialist.
To add a certificate to the list of trusted certificates:
Download the certificate. (If the linked file opens directly in the browser, click CTRL + S and save the file to your computer; you don't need to copy the text from the file.)
Open the Start menu.
In the search box, type certmgr.msc and press the Enter key.
In the program window, in the folder tree, click on the folder Trusted Root Certification Authorities.
In the right part of the window, right-click on Certificates and select All tasks → Import.
The Settings module is located in the Mail Menu. This module is designed to configure the mail server and contains three tabs: "Settings", "Spam protection" and "Address book".
Port SMTP/POP3/IMAP - allows you to change the standard ports for receiving and sending mail messages. The fields "Interfaces for SMTP" and "Interfaces for POP3/IMAP" are intended for specifying the interfaces set on the "X" on which the SMTP/POP3/IMAP protocols will work. By default, work goes on all interfaces. If you check the "Automatically create allow rule" box, the allow rule will be set in the firewall for SMTP/POP3/IMAP ports. You can go to the list of existing rules and configure them by clicking on the appeared hyperlink "Access to the mail server".
Mail server"X" by default works without encryption. To improve and ensure the security of the X mail server, you must configure this block.
The "Certificate for SMTP" field - allows you to select a certificate for the SMTP protocol from those entered on the "X". Enables the use of an encrypted connection using the STARTTLS method over the use of a regular TCP connection over SMTP protocol on standard port 25. This encryption is a compromise. If the remote party does not support encryption, then the message will be sent/received via the non-encrypted SMTP protocol.
The "Certificate for IMAP/POP3" field - allows you to select a certificate for the IMAP/POP3 protocols from those entered on the "X". Enables the use of an encrypted connection using the STARTTLS method over the use of a regular TCP connection using the IMAP/POP3 protocols on standard ports 143/110, respectively.
The "Enable SMTPS" and "Enable POP3S/IMAPS" flags allow you to enable encryption for the SMTPS, IMAPS, POP3S protocols on non-classic ports in parallel to 25/110/143 ports. The main difference is the mandatory use of encryption, no compromise is possible. The X mail server uses only TLSv1, TLSv1.1, TLSv1.2 cryptographic protocols. Use of SSL2 and SSL3 for security, disabled.
The fields "SMTPS port", "POP3S port", "IMAPS port" allow you to set the port numbers for the SMTPS, IMAPS, POP3S protocols, respectively.
The field "DH key length (Diffie-Hellman)" - allows you to set the key length for encryption using the STARTTLS method and for TLS cryptographic protocols, various versions, when using the IMAP/POP3 and IMAPS/POP3S protocols. It is worth noting that the recommended key length is 2048 bits, by default it is 1024 bits to optimize the first launch of X.
The following settings are needed to set various restrictions when sending emails:
The "Maximum message size" field - sets the limit for downloading attachments via web mail (built-in roundcube client).
Flag "Restrict frequent sending of letters" - includes restrictions on sending letters through the "X" mail server.
The field "Maximum number of letters from one IP address per minute" - sets the value of the maximum number of letters sent per minute from one IP address. This limitation does not apply to emails sent from the web interface of a pre-installed email client.
Flag "Ignore when sending emails from addresses and networks from the white list" - creates an exception in the restriction "Restrict frequent sending of emails" for IP addresses and networks specified in the "White list" block below.
Mail messages that have not been sent are queued for resending.
The following settings are needed to set different time intervals when resending mail messages:
The "Interval between sending attempts" field - allows you to set the start time of the daemon (the daemon is a program running in the background), after which it will check the time the message has been in the queue (30 minutes by default).
Queue timeout field - allows you to set the time interval for a message in the queue, during which the daemon will try to resend this message from the queue (by default, it ranges from 180 minutes to 300 minutes). For example, an email was not sent, while the default daemon starts every 30 minutes, which means that the daemon will start after the delta time, where delta can take a value from the interval - . Thus, re-sending will be made through 180+delta. If the resending did not occur, the message will again be sent to the sending queue, the counter of the time the message was in the queue becomes equal to zero, and the lower limit (in our case, 180 minutes) for this letter will be shifted automatically, but will not exceed the upper limit. Attempts to send the letter will be repeated until the total time the message was in the queue reaches the value specified in the "Maximum time the message was in the queue" field.
The "Maximum time the message was in the queue" field - allows you to specify the maximum total time the message was in the queue, after which the sender will be notified that his message was not sent (5760 minutes by default).
X can be configured to send outgoing mail through a different SMTP server for all emails, except for emails whose destination address is a local domain or recipient. In order to enable sending outgoing mail through another SMTP server, you need to register its address (domain name or IP) in the "default relay" field and set the port for connection. The "SSL" flag is used only for SMTPS connection on port 465. Thus, the flag for sending emails to destination port 465 is required. When connecting to port 25, the SSL flag should not be set, because connection encryption via STARTTLS extension will be selected automatically, depending on support this method encryption of the connection by the remote side. If the external SMTP server requires user authentication, then you must set the "Use SMTP authorization" flag and specify the user's login and password. It should be noted that when sending mail messages via the mail.ru / yandex.ru / gmail.com SMTP server, etc., it is necessary to set the flag “Substitute sender address”, because For these mail servers, the sender address (FROM header) must match the user under which authorization was performed, and also specify the sender address in the "Sender Address" field.
Allows you to add lists of white and black addresses from which incoming mail is allowed or denied. When you click on the "White List" button, a new dialog box will open, in which it is possible to add: IP address, domain name, network (including the one entered in "X"), mail server (for example, @mail.ru), mail box. From which "X" will always receive email messages without checking by gray lists and checking the correspondence of direct and reverse records in DNS, as well as without authorization. Attention! Only add senders you really trust to this list.
When you click on the "Blacklist" button, a new dialog box will open, in which you can add: IP address, domain name, network, mail server (for example, @mail.ru), mailbox. From which "X" will not accept mail messages.
This block allows you to select the mail domain entered on the "X" when authorizing the client. For example, on "X" the mail domain domain.local is set up, and the User, from this domain, is given the mailbox name - usermail. Then, when choosing “domain.local” in this block, the User, when accessing the “X” mail server through the mail client or through the web interface, in the “User name” field can only indicate - usermail, and not [email protected].
This block allows you to move the mail storage to a separate hard drive. By default, mail is stored in the main system partition (where X is installed). When changing the mail storage location, all letters will be copied from the current hard drive on new. The progress of copying mail from disk to disk can be monitored in Menu - Maintenance - System - Tasks. If the new hard disk already contains files with mail, then copying will not be performed (only for X 5.1.7 and higher).
Allows you to specify the hostname that will be passed in the SMTP HELO or EHLO command to the remote side when sending a message.
Allows you to set a list standard folders created in the mailbox. If necessary, you can change the composition.
This block includes checking incoming and outgoing messages for viruses. If the result is positive, instead of the letter itself, the recipient will receive a message about the results of the check, and the letter itself will be attached to the message. Antivirus scanning (Clamav, DrWeb, Kaspersky, to use the antivirus, you need to make the appropriate settings) is activated by setting the appropriate flag opposite the antivirus name.
Check DKIM signature flag. Enables checking incoming emails for the presence and validity of a DKIM signature.
Flag "Create DKIM signature". Activates the addition of a DKIM signature to letters sent from X.
Selector field. By default, X uses the default selector. Since there can be several mail servers for one domain, it is necessary to create a separate DKIM selector for each mail server in one domain.
When the flag is set, it enables scanning of mail messages by the DLP module (by setting the flag in Menu - Protection - DLP - Settings - the flag "Use DLP for mail"), provided correct setting and operation of the DLP module.
Allows you to set the "Recode subject to UTF-8" flag. If this flag is set, letters sent from the "X" mail server will have UTF-8 letter subject encoding.
This flag enables/disables support for UTF-8 encoding when receiving and sending emails.
In the "Spam Protection" tab, you can configure the servers that contain blacklists, as well as configure the graylist operation mode in "X".
This block allows you to add/remove hosts containing DNSBL blacklists. These lists are used to fight spam. When receiving a message, the X mail server contacts all the hosts specified in this list and checks whether they contain the IP address of the sender from which it receives the message. If there is no response or a positive response from one of the hosts, ICS considers that an attempt is being made to receive a spam message. The message is not accepted and a 5xx error (fatal error) is reported to the sender's server.
This block is designed to set automatic spam blocking. When you check the "Use Greylists" box, "X" will monitor the behavior of mail servers that send letters to "X". You can read about the blocking methodology https://ru.wikipedia.org/wiki/%D0%A1%D0%B5%D1%80%D1%8B%D0%B9_%D1%81%D0%BF%D0%B8% D1%81%D0%BE%D0%BA .
Greylists are configured according to three parameters - the "ignore resending" field in seconds (it is assumed that a reliable mail server will not resend a letter at this time); the "expect resending" field is indicated in hours (it is assumed that the letter should arrive no later than the specified time); the “keep in the white list” field is specified in days (it is assumed that the mail server that passed the check will not be subject to it for a certain number of days).
The "Address book" tab defines the parameters of the address book of the "X" mail server for the Users' client programs. Here you can determine the port on which LDAP is running, configure the Base DN parameter (search base for LDAP, you can specify several separated by semicolons), enable or disable the use of the address book, the flag "Use ICS Address Book". It is worth noting that this flag allows you to transfer the address book to all mail clients, but with this flag set, it is possible not to transfer the address book to Roundcube (the corresponding setting is made in the Menu - "Mail" - "Webmail" - "Settings" tab).
Examples of how to set up an SMTP server for Gmail, Yahoo, Hotmail, AOL accounts
Instructions for setting up an SMTP server
Enter your email address in the Email address field.
Enter the name of the outgoing mail server in the Server field.
Specify a port.
Enter your account name in the User field.
Enter your password in the Password field.
Enable the SSL option if the server needs a secure connection.
Gmail SMTP account settings 
Server: smtp.gmail.com
Port: 465
SSL: Option enabled
Note: Activate the "POP Download" or "IMAP Access" option in your Gmail account(Go to "Settings" -> "Forwarding and POP/IMAP").
Yahoo SMTP account settings
Server: smtp.mail.yahoo.com
Port: 465
SSL: Option enabled
Note: Enable "Web & POP Access" in your Yahoo account (Go to "Options" -> "Pop & Forwarding")
Hotmail SMTP account settings
Server: smtp.live.com
Port: 587
SSL: Option enabled
AOL SMTP account settings
Server: smtp.aol.com
Port: 587
SSL: Option enabled
Let's start with the oldest mail service Mail.ru. After completing a simple and understandable registration procedure, you will receive a mailbox in any of the four domains of your choice (mail.ru, inbox.ru, bk.ru, list.ru). The size of the mailbox is unlimited, initially equal to 10240 MB, as soon as your mailbox becomes less than 100 MB of free space, the volume can be increased by another 2 GB.
The maximum size of the letter you send should not exceed 30 megabytes, the number of recipients of the letter should not exceed 30.
To configure a local email client using the POP3 protocol, use the following options:
Incoming mail server (Incoming message server POP3 server) - pop.mail.ru; port 110 (no encryption) or 995 (with SSL encryption)
Outgoing mail server (SMTP server) - smtp.mail.ru; port 25, 587 or 2525 (no encryption) and 465 (with SSL encryption)
The username (login) on the POP server and on the SMTP server is the full name of your mailbox, including the username, the "@" dog icon and the domain (for example, [email protected]);
The features of this service include the ability to use a non-standard SMTP port 2525 in the settings (in addition to the standard 25 and 587) to bypass the prohibition of some Internet providers for outgoing TCP connections on port 25 and, alas, the complete lack of support for the IMAP protocol.
after sending 120 letters, there were significant delays in mail delivery (up to 40 minutes), after sending 182 letters, error 553 began to appear (the server does not want to send mail), which disappeared after a while (from 5 minutes to an hour) and arose again after sending letters. After 2 days, the restrictions continued to operate. The picture didn't change much even after sending responses to the initial mailing list (no more than 5 emails per hour). It is not advisable to use the free mail service Mail.ru, like any other free mail services, for any serious mailing.
In the Russian segment of the Internet, perhaps one of the most popular free mail services is Yandex.Mail.
Immediately after registration, the volume of the mailbox is 10 gigabytes. As soon as it has less than 200 megabytes left free space, the mailbox will automatically increase by 1 gigabyte, provided that the user regularly logs in, logs into the Yandex.Mail web interface using a browser.
It should be especially noted that for a newly created mailbox, you must first enable the use of the POP3 and (or) IMAP protocols in the Yandex.Mail web interface before you start working with this mailbox in your mail client. This feature, unfortunately, is a very common cause of failure to send and receive mail in an absolutely correctly configured mail client! Be careful!
So, here are the basic parameters for setting up a mail program using the POP3 protocol:
Incoming mail server (Incoming message server POP3 server) - pop.yandex.ru, port 110 (without encryption) or 995 (with SSL encryption)
Outgoing mail server (SMTP server) - smtp.yandex.ru; port 25 or 587 (no encryption) and 465 (with SSL encryption)
The username (login) on the POP server and on the SMTP server is, in this case, the first part of your email address before @yandex.ru, for example, if you have registered a mailbox [email protected], then "myname" should be specified as the username (without "@yandex.ru")
In the account settings, you must specify that the outgoing mail server (or SMTP server) requires authorization;
The basic settings for configuring an email program using the IMAP protocol are identical, with the exception of the incoming server:
Incoming mail server (IMAP server) - imap.yandex.ru, port 143 (without encryption) or 993 (with SSL encryption);
The maximum message size is 30 megabytes.
To the features of the service, you should add the so-called "one-time" addresses for your e-mail, which look like "your login + [email protected]", for example, [email protected] or [email protected]. A message sent to such an address will be delivered to your inbox. This feature can be useful in many cases where it is undesirable to report real address Email.
Another feature is mail aliases (pseudonyms) of your mailbox in the domains @narod.ru, @ya.ru, @yandex.by, @yandex.com, @yandex.kz, @yandex.ua.
You can enable and configure this feature in your account settings on the Yandex.Mail web server. Subsequently, you will be able to receive letters to the aliases you configured. For example, you created an alias (alias) [email protected] And [email protected]. Letters sent to these addresses will arrive in your inbox. For more information on these features, please refer to the relevant section. help system Yandex.Mail.
The service also does not declare restrictions on the frequency of sending. During the experiments, it turned out that after sending 90 letters, an error 550 occurred, in fact, after that it was possible to send no more than 4 letters per hour. The delivery time of letters did not fall.
After 2 days, the restrictions also continued to operate. On the 3rd day, after the generation of return letters, the possible delivery speed to new addresses exceeded 80 letters per hour and remained at this minimum for a day.
The parameters for setting up an email client using the POP3 protocol are as follows:
Incoming mail server (Incoming mail POP3 server) - mail.rambler.ru, port 110 (without encryption) or 995 (with SSL encryption);
Outgoing mail server (SMTP server) - mail.rambler.ru, port 25 or 587 (without encryption or STARTTLS encryption) and 465 (with SSL encryption);
The username (login) on the POP server and on the SMTP server is the full name of your mailbox, including the username, the "@" dog icon and the domain (for example, [email protected]);
In the account settings, you must specify that the outgoing mail server (or SMTP server) requires authorization;
The settings of the mail program using the IMAP protocol are identical, except for the incoming message server:
Incoming mail server (IMAP server) - mail.rambler.ru, port 143 (STARTTLS encryption) or 993 (SSL encryption);
Unencrypted IMAP connections are not allowed in this service. The configuration features include the requirement for the contents of the "From:" ("From:") field of the letter: the e-mail address you specified in the mail client settings must match the username that you use to log in to the SMTP server.
The size of files that can be attached to an email is limited to 20 megabytes.
