Hi, I have seen this problem in a lot of forums but I couldn't find an easy solution. We host about 90 domains in a single server sharing one IP. All our clients work fine sending mail except when destination is an AOL, BellSouth (or some universities) account. The message holds in the queue until seven days later is bounced with the error. AOL requires sender domain set a PTR record with a value. I've checked a lot of times AOL tool http://postmaster-us.info.aol.com/tools/rdns.html and always returns a valid PTR, our host server (ie: host3.ourhostserver.com). My question is: When our client (ie: email@example.com) send an email to AOL it checks PTR and always get the same our host PTR (host3.ourhostserver.com), not the domain name (ourclient.com). Is this the trouble? DNS settings for our host server are: xx.xx.xx.xx / 24 PTR ourhostserver.com. ftp.ourhostserver.com. CNAME ourhostserver.com. ourhostserver.com. NS ns1.ourhostserver.com. ourhostserver.com. NS ns2.ourhostserver.com. ourhostserver.com. A xx.xx.xx.xx ourhostserver.com. MX (10) mail.ourhostserver.com. ourhostserver.com. TXT v=spf1 a mx ~all host3.ourhostserver.com. A xx.xx.xx.xx mail.ourhostserver.com. A xx.xx.xx.xx ns1.ourhostserver.com. A xx.xx.xx.yy ns2.ourhostserver.com. A xx.xx.xx.zz webmail.ourhostserver.com. A xx.xx.xx.xx www.ourhostserver.com. CNAME ourhostserver.com. DNS settings for a typical domain are: xx.xx.xx.xx / 24 PTR ourclient.com. ftp.ourclient.com. CNAME ourclient.com. mail.ourclient.com. A xx.xx.xx.xx ourclient.com. NS ns1.ourhostserver.com. ourclient.com. NS ns2.ourhostserver.com. ourclient.com. A xx.xx.xx.xx ourclient.com. MX (10) mail.ourclient.com. ourclient.com. TXT v=spf1 a mx ~all webmail.ourclient.com. A xx.xx.xx.xx www.ourclient.com. CNAME ourclient.com. Any solution? Also I have checked that all destinations (AOL, BellSouth...) have MX records with same vale. aol.com. 307 IN MX 15 mailin-02.mx.aol.com. aol.com. 307 IN MX 15 mailin-03.mx.aol.com. aol.com. 307 IN MX 15 mailin-04.mx.aol.com. aol.com. 307 IN MX 15 mailin-01.mx.aol.com. bellsouth.net. 6421 IN MX 10 gateway-f1.isp.att.net. bellsouth.net. 6421 IN MX 10 gateway-f2.isp.att.net. May this mess up Qmail? Also when destination is a Yahoo account messages hold in the queue for more than an hour but they finally arrive. Thanks. Alejandro.