Dopo aver inviato una mail ad un indirizzo che so per certo essere funzionante mi è arrivata questa e-mail:
Subject: Warning: could not send message for past 4 hours
> **********************************************
> ** THIS IS A WARNING MESSAGE ONLY **
> ** YOU DO NOT NEED TO RESEND YOUR MESSAGE **
> **********************************************
>
> The original message was received at Mon, 13 Mar 2006 14:35:00 GMT
> from [xx.xx.xxx.xx]
>
> ----- Transcript of session follows -----
> ... while talking to mailin-03.mx.aol.com.:
> >>> DATA
> <<< 421-: (DNS:NR) http://postmaster.info.aol.com/errors/421dnsnr.html
> <<< 421 SERVICE NOT AVAILABLE
> ... while talking to mailin-04.mx.aol.com.:
> >>> DATA
> <<< 421-: (DNS:NR) http://postmaster.info.aol.com/errors/421dnsnr.html
> <<< 421 SERVICE NOT AVAILABLE
> ... while talking to mailin-02.mx.aol.com.:
> >>> DATA
> <<< 421-: (DNS:NR) http://postmaster.info.aol.com/errors/421dnsnr.html
> <<< 421 SERVICE NOT AVAILABLE
> ... while talking to mailin-01.mx.aol.com.:
> >>> DATA
> <<< 421-: (DNS:NR) http://postmaster.info.aol.com/errors/421dnsnr.html
> <<< 421 SERVICE NOT AVAILABLE
> <xxxxxxxxxxxxx@aol.com>... Deferred: 421-: (DNS:NR)
http://postmaster.info.aol.com/errors/421dnsnr.html
> Warning: message still undelivered after 4 hours
> Will keep trying until message is 5 days old
>
Andando a vedere uno dei link sopra riportati ho trovato questa spiegazione all'errore:
EXPLANATION:
Reverse DNS lookup for your IP address is failing. AOL does require that all connecting Mail Transfer Agents have established reverse DNS.
SOLUTION:
Reverse DNS is a way of associating an IP address with its domain name. The reverse DNS identifier is contained in the PTR portion of the IP Zone File. You may look at your reverse DNS using our reverse DNS search tool.
If you are on a dynamic IP address, please call your ISP and request a static IP address with proper rDNS before attempting to send mail to AOL through that server.
If you are on a static IP address, please call your ISP or DNS provider and ask them to establish a reverse DNS record for your IP address, reflecting your correct domain name.
For additional information on reverse DNS, please visit http://postmaster.info.aol.com/info/rdns.html .
Purtroppo non so benissimo l'inglese e comunque non ho capito nulla di quello che è stato detto...
Qualcuno sa spiegarmi cosa significa tutto ciò?
P.S le "x" logicamente sono in sostituzione dell'indirizzo IP e della mail che erano riportate nel messaggio arrivatomi.