Your External IP Address is:
This page can be used to set your $email_localname parameter.
YOU MUST CHECK THIS PAGE FROM EACH MACHINE THAT HAS EMAIL
Do NOT use the value which appears on your personal desktop machine when you visit this page.
Note that different machines on your network may have different external IP addresses, though on some network configurations different machines may present the same external IP address.
Add an $email_localname command to your faxfacts.cfg file on each machine which will send email. For example for an email only installation enter the line:
$email_localname * 
The first parameter "*" indicates the line group(s) that this command will apply to and should be replaced with a line group name or line range if you use more than one machine for CopiaFacts email and so need multiple $email_localname commands. An "*" indicates all lines(threads) in your system and is the recommended setting for a system in which only one machine is used for CopiaFacts email.
Reverse DNS Look-up, PTR Records
Reverse DNS look-ups will resolve the IP address you see above into a fully qualified domain name (FQDN). This is done via a PTR, or pointer record. A PTR is a DNS record that takes an IP address and points it to a domain name. An IP address may only have a single PTR record. So, any ONE IP address can only be reverse validated to a single domain name.
To combat spam and zombie mail senders, many remote mail servers now require that the IP address you send email from must be capable of being resolved to a domain name using reverse DNS lookup. To send email into these servers, you should ensure that the DNS name for your machine running CopiaFacts, matches the value from the tool below. If it does not, you will have to contact your ISP or IP address provider and request that they configure their DNS servers.
For any additional help please contact our support department or refer to the reference manual under $email_localname