Spam & SBC

[ibe98765]

Received this from SBC today where I have a hosted domain account. Unfortunately, it has impacted a forwarding service I use and I have been working with that service trying to figure out what was going on. Nice of SBC to let its customers know about making such a major change 10 days after they implemented it. Must be getting a lot of complaints.Can anyone tell me if turning on "reverse DNS lookup" IS some kind of recommendation or standard?

Dear Customer,In an effort to reduce the amount of spam delivered to our customers, as of June 11, 2004, SBC has enabled two spam prevention measures on our mail servers.  We will now reject email from servers that do not have reverse DNS (rDNS) setup on their IP address or that are listed on a black list of dynamic IP addresses. Most Internet Service Providers (ISP) and customers running their own name servers have this function turned on by default. If they don't, customers will receive a bounce back email stating that "reverse look up failed". This can impact both domestic and international customers. If a customer receives the bounce back message they should contact their ISP (or their company mail administrator) and request that reverse DNS be turned on. This is an industry standard and any reputable ISP should respond quickly. Below is more detail on the measures we've taken. - The Sorbs DUHL (Dynamic User Host List) black list contains IP addresses, assigned in a dynamic fashion, by an ISP for an Internet connection.  This protocol (DHCP for example) is widely used for those Internet users who have dial-up, DSL, ADSL and Cable connections. These types of Internet access users should relay mail through their ISP's authorized relays.  In fact, most of the IP's on this list were actually supplied to Sorbs by the ISP's who maintain these IP's.- rDNS checking (PTR record).  Each connection made to deliver email to your domain will have a rDNS check made against the IP.  If the IP address making the connection does NOT have a PTR record, the connection will be denied.  Anyone that wishes to send email to our servers and does not have a reverse DNS entry for their IP address will need to contact their Internet access provider to have this setup.If you have any questions please call Technical Support at 1-888-WEBHOST.Thank You,SBC Shared Web Hosting Customer Care

[nlinecomputers]

Yes and no. It is laid out in RFC 1035 which was published in 1987 but not often used until the last couple of years as a method to combat spam.So you not fully following internet standards if you don't do this and a lot of small fry don't know to use it. AT&T has been using this as a filter for some time now.http://www.faqs.org/rfcs/rfc1035.htmlHere is a microsoft article on it.http://www.faqs.org/rfcs/rfc1035.html