On 08/17/2010 01:27 PM, Gordon Messmer wrote: > On 08/17/2010 09:33 AM, JD wrote: >> Re: a.b.c.d ==> valid.host.name >> and valid.host.name ==> a.b.c.d >> does not seem to apply to the google smtp server I use for Thunderbird. > You did your test entirely backward. You did a forward lookup first, > and then checked the PTR of the IP which was returned. There is no > requirement for a PTR to match every hostname that resolves to its IP > address. > > Let's finish your test: > > $ host smtp.gmail.com > smtp.gmail.com is an alias for gmail-smtp-msa.l.google.com. > gmail-smtp-msa.l.google.com has address 74.125.155.109 > > The result of this test merely identifies an IP address. Now, let's > test to validate that the IP returns a PTR that resolves to the same IP: > > $ host 74.125.155.109 > 109.155.125.74.in-addr.arpa domain name pointer px-in-f109.1e100.net. > $ host px-in-f109.1e100.net. > px-in-f109.1e100.net has address 74.125.155.109 > > Yep, totally valid. That IP address has a PTR record, and the hostname > contained in that PTR resolves back to the same IP address. This host > is properly configured. > >> So, Thunderbird client does not seem to mind that >> reverse lookup does not match the name smtp.gmail.com > Clients rarely do. It's the servers to which you're going to try to > deliver mail that will mind. I see! Thanks for the heads up! At any rate, I am having serious problem with an unwieldy router. I just posted a message about that. -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
