On 2/4/2015 1:47 PM, Robert Moskowitz wrote: > I have been 'working' with my new ISP for a couple weeks to get the > rDNS setup for my server move (I am changing ISPs for a number of > reasons). I was assured on signing that setting up rDNS was 'easy'; > it is not. DIGing up the SOA on my IP rDNS tends to indicate that > they have not updated that zone for many months. > > Anyway,,, > > A friend using the same ISP 'solved' this by changing his SMTP > server to say the mail for his domain is ok to come from the ISP PTR > value. So let's say that: > > My server is: z9m9z.htt-consult.com > > And further assume that the reverse for the address where I want to > move it to has a PTR of > > 9.254.253.50.in-addr.arpa. 3600 IN PTR > 50-253-254-9-static.hfc.comcastbusiness.net. > > And that 50-253-254-9-static.hfc.comcastbusiness.net has no RR (e.g. > A or CNAME). > > Is there someway to get postfix to provide the needed inforation to > the recipient MTA that this is OK and valid? > > I am asking, but I suspect that even if I send out things OK, there > will be MTAs out there that will not let their clients send mail to > me as my rDNS does not match. > > I am pushing the ISP that will remain unnamed. (oops. :) ) I was > told that 'they are working on it'. Meanwhile I am paying double as > I cannot migrate my server. > > I will be pleased if there is a real workaround, but not overly > disappointed if the only way out is through. > >
Don't worry about *receiving* mail. Other systems sending you mail don't care a bit about what the name of your MX server is, or what kind of IP it's hosted on, as long as the MX name resolves to the correct IP. Feel free to reuse your current z9m9z.htt-consult.com as an MX name, or use something totally different. There are potential problems with *sending* mail. All the comcast business IPs that I know of already have proper FCrDNS. This is necessary to communicate with sites that use "reject_unknown_client_hostname" or similar. If your new IP's PTR has no matching A record, get that solved first before you tackle trying to get a custom PTR. This should be an easier problem to fix. Once you have FCrDNS (even with an unwanted PTR name), you should be able to safely move. Do some testing -- just hook some PC up to the new connection and use telnet (or the very handy mini_smtp tool) to send some test mails directly to various servers. Configure postfix with a HELO name (smtp_helo_name) something like "z9m9z.htt-consult.com" rather than the more technically correct PTR name. Make sure the HELO hostname has an A record pointing to your IP. (bonus points for a name containing smtp, e?mail, mx, mta, etc.) This helps you look more like a mail server and less like a bot. Make sure you have an SPF record including your IP. If you use the same IP for sending and receiving, just include the spf "mx" key. (looks as if you have that already... good) -- Noel Jones
