Hi,

I have Exchange 2013 one CAS and one Mailbox server and configured multiple users on POP and IMAP. The problem is on Client Frontend security settings the anonymous is selected and port 587 is allowed on Firewall. If someone from outside telnet on our domain on port 587 they can send email to any outside domain and 587 port is acting as relay.

The problem is when I uncheck the anonymous on Client Frontend on port 587 in security option the telnet from outside stop but my local users who were configured on POP were unable to send email. In client computer, change the POP port from 587 to 25 the user send and receive email but the problem is to uncheck on the "server required authentication".  I want to enable the "server required authentication" on port 25.

I am having permission conflict on the configuration what I think so. Can some one help me to find the solution.

Hi Lucky,

I recommend you run the following command and check you send connector settings:

Get-SendConnector |fl

In general, if you use 25 port to send email, it usually use send connector to route the email, however, if Send connector is configured with Proxy through Client Access server in the Exchange admin center or -FrontEndProxyEnabled $true in the Exchange Management Shell, Outbound mail will be routed through a Client Access server only.

If the email route through CAS server, you can try to configure the permission to meet your requirement.

I recommend you refer to the following article to understand more details:

Network ports for clients and mail flow in Exchange 2013

Best regards,

Hi Lucky Hamu,

This is the default settings for the Client Frontend receive connector .So please make sure your exchange server has same settings as mentioned on the given snap.

Note : For pop connectivity only port no 995 (i.e for receiving )and 587 (i.e for sending) needed to be opened on the firewall.



Please reply me if you have any queries.

Hi,

Users unable to send and received email internally and externally.

Kindly let me know which third party application are you using for downloading emails.

Regards,

Exchange Support

Hi Nithyanandham,

I followed your suggestion and configured the default settings on Client connector as you shared. The result is users who are connecting POP from internet having issue that some time they send emails and some times get receive error and email get stuck in outbox. After again select the anonymous checkbox email is working fine.

Hi Redhat,

No third party application is running we are using MS outlook different versions, 2003, 2007, 2010 for downloading emails.

Kindly suggest how user can send email without any problem after unchecking the anonymous option.

• Edited by Lucky-Hamu 23 hours 38 minutes ago

Hi ,

Then please share me your error message .

Hi Nithyanandham,

I followed your suggestion and configured the default settings on Client connector as you shared. The result is users who are connecting POP from internet having issue that some time they send emails and some times get receive error and email get stuck in outbox. After again select the anonymous checkbox email is working fine.

Hi Redhat,

No third party application is running we are using MS outlook different versions, 2003, 2007, 2010 for downloading emails.

Kindly suggest how user can send email without any problem after unchecking the anonymous option.

• Edited by Lucky-Hamu Friday, May 15, 2015 7:50 AM

Hi Nithyanandham,

I followed your suggestion and configured the default settings on Client connector as you shared. The result is users who are connecting POP from internet having issue that some time they send emails and some times get receive error and email get stuck in outbox. After again select the anonymous checkbox email is working fine.

Hi Redhat,

No third party application is running we are using MS outlook different versions, 2003, 2007, 2010 for downloading emails.

Kindly suggest how user can send email without any problem after unchecking the anonymous option.

• Edited by Lucky-Hamu Friday, May 15, 2015 7:50 AM

Hi,

Receiving error messages are:

Send test email message Faied.

Task - Sending error (0x800CCC78) ;  Unable to send message. Please verify  the email address in your account properties. The server responded: 530.5.7.1 Clietn was not autheticated

Please help

Hi Lucky Hamu ,

Thanks for your reply.

1.First i just want to ensure that you have the default settings on the Client Frontend receive connectors in all of your cas servers .

2.Then share me the snaps for the email client account configuration settings.

3. All the pop and imap connections from the cas server are proxied to the connector "Client Proxy " which will be available on the mailbox server.So please make sure the below settings are available on the mentioned connector in the mailbox server.

Below snap is for the connector "Client Proxy" in mailbox server :

Hi Nithyanandham,

I have verified the settings on Client Proxy and the configuration is same as you shared in image. The Client End settings snap shots attached for your reference.

On Client Frontend Receive connector until I check mark on  "Anonymous Users" then users are able to send emails.

Kindly help to resolve this issue.

Thanks