I have a virtual server using a fixed external ip and operating as a dedicated Exchange Server 2013 with Windows Server 2012 Standard. I have migrated accounts over from another VM running Exchange 2007. All recipients, accepted domains, policies etc appear to have been imported but I am facing some challenges configuring Exchange 2013 to relay external mail. Internal mail relays just fine and mail is being received from both internal and external sources.

I have two Send Connectors set up.

The first was created during Exchange Setup:

General
Name: To Internet
Connector Status: Enable
Comment: Null
Protocol Logging level: None
Maximum Message Size: 50MB

Delivery
Send mail connector: MX record associated with recipient domain
Smart Host: Null
Use external DNS lookup on servers with transport roles: Unchecked

Scoping
Type: SMTP
Domain:*
Cost:10
Scoped send connector: Unchecked
Source server: My 2007 server & My 2013 Server
FQDN: My 2013 servers external domain name

The second I created to try and overcome the problem by using a Smart Host albeit my host restrict the volume of mail allowed and so this would be inadequate in the long term but in any event a test mail was rejected by their server:

General
Name: Send Internet Mail
Connector Status: Enable
Comment: Null
Protocol Logging level: None
Maximum Message Size: 10MB

Delivery
Send mail connector: Route mail through smart host
Smart Host: My providers smart host
Authentication: Basic using my account details
Use external DNS lookup on servers with transport roles: Checked

Scoping
Type: SMTP
Domain:*
Cost:1
Scoped send connector: Unchecked
Source server: My 2013 Server
FQDN:NULL

Initially I was getting "unable to relay" messages but with the various tweaks and changes I've made I have overcome this and now I get "delivery delayed" messages so it seems the mail is queuing but not getting sent.

Any help would be very much apprec

Update.

I had a typing error in my hosts relay settings. Now fixed I am able to send through them but I really want to manage this locally as I did in Exchange 2007.

So for now Send Connector "To Internet" is disabled and  Send Internet Mail is working using an external Smart

I finally got to the truth of this matter. My host blocks port 25 outgoing and restricts the volume of mail through their smart host to 100 messages per day. So, I now know why I was having such intermittent problems. I am angry with them because:

1. The world at large listens on port 25 for incoming mail.
2. My server hosted with them cannot disseminate email because they block port 25.
3. At no time during the sales process did they mention that they block port 25.
4. My VM set up as a dedicated Exchange Server cannot function.
5. Their relay is very restrictive.
6. They suggest I route to another external facility to process my mail.
7. They gave misleading information resulted in several days lost productivity when they denied that they blocked port 25 only to later clarify that they do indeed block it outbound.

Anyway now that I understand the challenge I wonder if anyone has a solution to route email through an external smart host in the UK at a low cost? We probably sent up to 100,000 emails per month.