TOPIC
How do I set up an AppleShare IP 6.x Mail Server within the private network set up by a router that performs Network Address Translation (NAT, also known as IP Masquerading)?
DISCUSSION
There are five main steps to setting up ASIP 6.x mail services inside a NAT environment:
2. Mapping incoming traffic. 3. Setting up the AppleShare IP (ASIP) Host Name list. 4. Configuring internal DNS. 5. Changing the SMTP Response Name. Step One: Configuring External DNS You must coordinate with your Internet Service Provider (ISP) to set up external DNS. Your ISP must configure DNS so that there is a permanent host name (or A Record) for the public IP address of the NAT router. If you have your own domain name, you may also want your ISP to set up a mail exchange record (MX Record) in their DNS so that any mail addressed to your domain name will be sent to the NAT router through the NAT router's permanent host name. For example, if your ISP created a host name (A Record) of "mail.company.com" for your public IP address, any email sent to user@mail.company.com would be sent to your NAT router. If your ISP created an MX Record for "company.com", any email sent to user@company.com would be sent to mail.company.com, which is again your NAT router. For specifics on how DNS should be set up to handle a mail server, see the following article: Article 24693: " AppleShare IP Mail Server: DNS Configuration " Step Two: Mapping Incoming Traffic Once you have service directed to your NAT router, you need to configure the NAT router to forward email traffic to your mail server. You will need to map incoming SMTP traffic (TCP port 25) on the NAT router to the private, internal IP address of the machine running the AppleShare IP Mail Server. This tells the NAT router to send all SMTP traffic to the mail server. If you want to provide external mail retrieval, you must also map POP3 (TCP port 110) and/or IMAP (TCP port 143) on the NAT router to the private IP address of the mail server. This will allow email clients to connect to the mail server through the NAT router. See the documentation for your particular NAT product for help setting up these port mappings. Step Three: Setting Up the ASIP Host Name List The ASIP Mail Server now needs to be configured to recognize that any email addressed to the public host name (for example, mail.company.com) should be considered local.
2. Start the Mail Server. 3. Choose "Show Host List" from the Server menu. 4. Click the "New Host" icon in the Host List window. 5. Enter the public host name of the NAT server (for example, mail.company.com). 6. Wait for this host to appear in the host list. 7. Select the host name you just entered. 8. Click the "Edit Host" icon. 9. Click the tab labeled "Mail To". 10. Check the box labeled "Relay all SMTP mail via". 11. Enter the private IP address of the ASIP mail server. 12. Click "Save" and close the window. The ASIP Mail Server will now treat this host as "itself" and properly deliver the mail to the mail accounts on the local system instead of trying to forward the mail back to the public host name. Note: The Host List window will not immediately list the host as "local". Instead, the first time the mail server encounters a message with a recipient for that host name, it will "resolve" the host and mark it as local. This process is deferred to avoid unnecessary DNS traffic until the mail server uses the hostname for the first time. At this point, email services are fully configured for sending and receiving email through the outside network. Email clients on the outside network should now be configured as follows: SMTP server: <public host name> POP/IMAP server: <public host name> Account name: user@public_host_name The domain name may be substituted for the public host name if a mail exchange record has been set up. If you have not configured internal DNS, any email clients trying to connect to the server from within the private network must be configured by IP address. If internal DNS has not been set up, mail clients on the private network should be configured as follows: SMTP server: <private IP address of server> POP/IMAP server: <private IP address of server> Account name: user@public_host_name The domain name may be substituted for the public host name if a mail exchange record has been set up. Note: If internal DNS is not set up, the mail server error logs will show reverse lookup errors on mail server startup. For more information, see the following article: Article 24689: " AppleShare IP Mail Server: Shows IP Address Instead Of DNS Name " Step Four: Configuring Internal DNS Configuring internal DNS allows clients on the private network to connect to the server by host name instead of by IP address. If you are using MacDNS for your internal DNS, see the MacDNS Administrator guide for a full explanation of how to set up MacDNS. For help with basic setup, see the following article: Article 31067: " Mac DNS: Configuration & Setup " When you set up internal DNS, note the following two points:
Once internal DNS is configured, email clients on the private network should be configured as follows: SMTP server: <internal host name of server> POP/IMAP server: <internal host name of server> Account name: user@public_host_name The domain name may be substituted for the public host name if a mail exchange record has been set up. Step Five: Changing the SMTP Response Name Finally, to ensure that other mail servers accept your email, you should set the name of the SMTP in and out response name to match your public host name. In AppleShare IP Mail Admin: |
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| Document Information | |
| Product Area: | Apple Software; Communications-Networking |
| Category: | AppleShare |
| Sub Category: | AppleShare for Mac OS |
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