Technical Standards for E-mail Delivery
The following technical requirements apply to the delivery of Internet e-mail through Frontier's e-mail network. In all cases we refer to the pertinent RFCs and strive to be standards compliant.
Frontier's mail servers:
- Will not accept connections from unsecured systems. This includes open relays, open proxies, or any other system that has been determined to be available for unauthorized use.
- Will not accept connections from known spam sources.
- Will not accept connections from systems that use dynamically assigned or residential IP addresses.
- Will not accept connections from any IP addresses that do not have reverse DNS (PTR record) and may refuse or rate limit connections from hosts without a matching DNS A record. See RFC 1912, section 2.1.
- Will not accept connections from systems that do not send a helo with a valid hostname or domain name.
- Will refuse bounce messages (i.e. messages with null sender) to more than one recipient. See RFC 2821.
- Will refuse messages without a valid or properly formatted 'mail from' addresses.
- Will refuse messages sent through an http proxy.
- May refuse connections from systems that do not accept bounce messages.
- May rate limit connections or messages based on the number of connections, messages sent, or recipients during a specific period of time.
- May refuse connections from systems that, through their actions, cause a denial of service.
Additionally, all incoming and outgoing messages must pass anti-spam and anti-virus checks based on current trends on the Internet.