OpenSRS offers an effective, low-cost email filtering service specifically designed for the needs of service providers. The Email Filter-Only service stands between your email servers and the Internet, acting as a gateway that protects your users and infrastructure from email threats like spam and viruses.
How the OpenSRS email filter-only service works
OpenSRS Email Filter-Only Service evaluates each and every email message using the latest in scanning technology to make a determination as to whether the content of the message is legitimate and wanted, or contains spam, phishing attacks, or a virus payload.
If the message is deemed legitimate, it's delivered to the recipient's email inbox. If the message is deemed spam, the subject line can be tagged, and a custom configurable header can be added to the message for delivery by your existing mail server to your users' inboxes, or designated spam folder. You may also chose to have spam delivered to a web-based Spam Quarantine where the recipient can periodically login to view and review messages flagged as spam. If a message contains a virus, it is simply discarded, protecting your users from infection.
Implementation steps
The steps to implement the Email Filter-Only system are as follows:
- Create a new domain profile for the domain name being filtered.
- Create email addresses using the Add User or Bulk Create options in the MAC.
- Set up access to the web-based Spam Portal using the domain name’s DNS servers, implementing a CNAME record to point to the OpenSRS Email Service system.
- Set up outbound mail filtering.
- Educate your users about the new anti-spam system.
- Change the MX record in the domain name's DNS servers to the OpenSRS Email Filter-Only Service. This will force incoming email to pass through the OpenSRS Email Filter-Only Service anti-spam system.
- Test email accounts on your system to see if email is flowing through the OpenSRS Email Filter-Only Service and then to your mail server.
These steps can be completed in the Control Panel or in the MAC.
Step 1: Create a new domain
You need to create a new domain profile so that the OpenSRS Email Filter-Only System understands that it should handle its mail flow. This is also where you specify the options that apply to the entire domain, such as the location of your mail server and the email addresses or systems that should not be examined by the OpenSRS Email Filter-Only System.
To create a new domain in the Control Panel
1. In the Email section of the Control Panel, click the Email Domains tab.
2. Click the plus sign (+) at the top of the page.
3. Enter the domain name in the text field, and then click Add.
4. On the Settings tab, click Edit in each section to edit the related fields, and then click Save.
Make sure that you complete the following fields:
- Filter MX Host—The MX Host address is the target mailserver to which filtered spam and virus-free email will be delivered. This can be either a hostname or IP address, and it must include the inbound port that accepts connections (usually port 25). For example, mail.mymailserver.com:25.
- Aliases—Enter any domain aliases.
-
Filter Delivery—From the drop-down list, choose the way in which you want spam messages to be handled by the OpenSRS email filters:
- Passthrough—Allow spam messages to be delivered to the Reseller's designated mailserver.
- Quarantine—Do not deliver spam messages to the Reseller's server.
- Spam Folder—Specify the name of the folder to which all spam messages will be delivered. The default is Spam.
- Spam Header—Specify the tag that the OpenSRS filters will add to the spam message headers so that your system will know that the messages have already been identified as spam.
- Spam Tag—Specify the tag that is appended to the Subject line of all spam messages.
Step 2: Create anti-spam filter-only accounts
All email addresses that exist in your mail server must have accounts created in the OpenSRS Email Filter-Only system. This enables the anti-spam filter, and allows valid email to pass through to your mail server. You can create accounts in two ways: create individual filter accounts or create multiple accounts at once using the Bulk Tools.
Creating a single filter account
To create a new filter-only account
1. In the Email section of the Control Panel, click the Email Domains tab and then click the domain under which you want to create the user.
2. Click the plus sign (+).
3. On the Add a User page, enter the user name that you want to create, and then click Add.
The User Settings page opens.
4. In the Mailbox User section, click Edit.
5. In the Type field, choose Filter.
The rest of the fields are optional.
6. Click Save.
Creating filter accounts in bulk
To bulk create new filter accounts
1. In the Email section of the Control Panel, click the Email Domains tab.
2. Click the domain you want to edit, and then click the Bulk Tools tab.
3. Click the button beside Bulk Add.
4. Enter the account information in the text area. Each Filter-Only account requires a single line as follows:
[user@domain.com],filter,[password],,,[Firstname],[Lastname],
Firstname and Lastname are optional
Example:
john@mydomain.com,filter,abc123!,,,John,Moore,
5. Click Submit.
Step 3: Set up your anti-spam portal
If you chose to have the Email Filter system quarantine spam, you need to supply your users with an interface where they can log in to view the captured spam. This tool allows them to release emails that were captured as spam in error.
If you set the Filter Delivery to passthrough, then you do not need to give your users access to a spam portal. Domains that use the passthrough setting deliver all spam to your server, and add additional information to emails identified as spam.
To create a portal, create a CNAME record in your DNS server that points to a special hostname based on the domain name you are having filtered. For the domain name example.com, the anti-spam portal located at portal.example.com points to mail.example.com.cust.[cluster].hostedemail.com. The DNS record looks similar to:
portal.example.com in cname mail.example.com.cust.[cluster].hostedemail.comYou can use either portal or spam as part of the hostname that points to the web based spam portal. Using either of these terms ensures that the portal login button displays Log in to Spam Quarantine. Using any other term causes the login button to display Log in to Webmail.
Step 4: Set up outbound mail filtering
Filter accounts can send mail through our SMTP service, and logging into the SMTP service requires the use of a user's full email address and password (SMTP AUTH).
Resellers can use the same portal CNAME directive for access to the SMTP service or can create an additional CNAME record in your DNS server for the outbound mail service. For example:
smtp.example.com in cname mail.example.com.cust.[cluster].hostedemail.comUsing the above example, users can then set their email software client outbound mail server to smtp.example.com and have mail scanned for spam on outbound delivery.
Step 5: Inform your users about the new anti-spam system
You need to inform the users of your email system that changes will be made to the flow of email to their account. If you are taking advantage of the Quarantine system, they need to know where you have set up the Anti-Spam Portal and their username and password. They should also be given instructions on how to manage Safe and Block sender lists and how to release quarantined mail.
If you have set the system to pass through spam to your users, they should be informed how this spam can be identified, either by a modified Subject line or extra information in the header of the email.
Step 6: Update the MX record in the domain name's DNS servers
Once the accounts have been created and the FilterMX has been set to the destination mail server, you need to update the MX record in the DNS server for the domain name. This causes all incoming mail for the domain name to be delivered to the OpenSRS Email Service anti-spam system before being delivered to the destination mail server.
Example MX record:
example.com. IN MX 0 mx.example.com.cust.[cluster].hostedemail.comStep 7: Ensure that mail is accepted by your mail server
Once you've changed your domain's MX record to point to the OpenSRS Email Filter-Only Service, send some mail through to test its delivery to our mail server. If the email is not received, check the web based Spam Quarantine Portal to see if it was flagged as spam. You can also consult the connection and delivery logs of your mail server to determine the cause of the problem.
Certain mail servers may need to be configured to accept mail from our Filter-Only service. Connections will be received from hostedemail.com. Depending on the mail server being used, you may need to allow mail relaying from hostedemail.com, or you may need to configure the mail server to regard mail for the domain as being handled locally.
Step 1: Create a new domain inside the MAC
You need to create a new domain profile in the MAC so that the OpenSRS Email Filter-Only System understands that it should handle its mail flow. This is also where you specify the options that apply to the entire domain, such as the location of your mail server and the email addresses or systems that should not be examined by the OpenSRS Email Filter-Only System.
To create a new domain
- In the navigation pane, click Add Domain.
The Create Domain page appears. - Complete the following fields:
3. Click Create.
Step 2: Create anti-spam filter-only accounts
All email addresses that exist in your mail server must have accounts created in the OpenSRS Email Filter-Only system. This enables the anti-spam filter, and allows valid email to pass through to your mail server. You can create accounts in two ways: create individual filter accounts or create multiple accounts at once using the Bulk Action tool.
Creating a single filter account
A filter account functions as a spam quarantine, trapping all spam and allowing good mail to flow through to a target account on your mail server.
To create a new filter-only mailbox
1. In the navigation pane, click Add User.
2. Complete the following fields:
- User - Enter a name for the new user, and then press the Enter key.
- Password - Specify the password to log in to the user’s Quarantine Portal
- Type - Choose Filteronly.
Note: All fields are disabled until you enter complete the User field and press Enter.
The rest of the fields are optional; see "Creating mailbox accounts" for an explanation of these fields.
3. Click Create or Create & Repeat. If you click Create & Repeat, the new user is created, and the Create User window remains open so that you can create another user.
Creating filter accounts in bulk
Bulk Action can be used to create any mailbox type, including Filter accounts.
To bulk create new accounts
1. In the navigation pane, click Bulk Action.
2. Keep the operation as Add.
3. Enter the account information in the text area. Each Filter-Only account requires a single line as follows:
[user@domain.com],filter,[password],,,[Firstname],[Lastname],
Firstname and Lastname are optional
Example:
john@mydomain.com,filter,abc123!,,,John,Moore,
4. Click Process.
Note: Creating domain profiles using the Bulk Action tool does not set the Filter MX Host variable; each domain profile needs to be updated with the required value.
Step 3: Set up your anti-spam portal
If you chose to have the Email Filter system quarantine spam, you need to supply your users with an interface where they can log in to view the captured spam. This tool allows them to release emails that were captured as spam in error.
If you set the Filter Delivery to passthrough, then you do not need to give your users access to a spam portal. Domains that use the passthrough setting deliver all spam to your server, and add additional information to emails identified as spam.
To create a portal, create a CNAME record in your DNS server that points to a special hostname based on the domain name you are having filtered. For the domain name example.com, the anti-spam portal located at portal.example.com points to mail.example.com.cust.[cluster].hostedemail.com. The DNS record looks similar to:
portal.example.com in cname mail.example.com.cust.[cluster].hostedemail.comYou can use either portal or spam as part of the hostname that points to the web based spam portal. Using either of these terms ensures that the portal login button displays Log in to Spam Quarantine. Using any other term causes the login button to display Log in to Webmail.
Step 4: Set up outbound mail filtering
Filter accounts can send mail through our SMTP service, and logging into the SMTP service requires the use of a user's full email address and password (SMTP AUTH).
Resellers can use the same portal CNAME directive for access to the SMTP service or can create an additional CNAME record in your DNS server for the outbound mail service. For example:
smtp.example.com in cname mail.example.com.cust.[cluster].hostedemail.comUsing the above example, users can then set their email software client outbound mail server to smtp.example.com and have mail scanned for spam on outbound delivery.
Step 5: Inform your users about the new anti-spam system
You need to inform the users of your email system that changes will be made to the flow of email to their account. If you are taking advantage of the Quarantine system, they need to know where you have set up the Anti-Spam Portal and their username and password. They should also be given instructions on how to manage Safe and Block sender lists and how to release quarantined mail.
If you have set the system to pass through spam to your users, they should be informed how this spam can be identified, either by a modified Subject line or extra information in the header of the email.
Step 6: Update the MX record in the domain name's DNS servers
Once the accounts have been created in the MAC and the FilterMX has been set to the destination mail server, you need to update the MX record in the DNS server for the domain name. This causes all incoming mail for the domain name to be delivered to the OpenSRS Email Service anti-spam system before being delivered to the destination mail server.
Example MX record:
example.com. IN MX 0 mx.example.com.cust.[cluster].hostedemail.comStep 7: Ensure that mail is accepted by your mail server
Once you've changed your domain's MX record to point to the OpenSRS Email Filter-Only Service, send some mail through to test its delivery to our mail server. If the email is not received, check the web based Spam Quarantine Portal to see if it was flagged as spam. You can also consult the connection and delivery logs of your mail server to determine the cause of the problem.
Certain mail servers may need to be configured to accept mail from our Filter-Only service. Connections will be received from hostedemail.com. Depending on the mail server being used, you may need to allow mail relaying from hostedemail.com, or you may need to configure the mail server to regard mail for the domain as being handled locally.
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