I have this case in exchange server 2007 the issue is exchange server ((cant send mail to outside 1-smtp connector (from exchange is ok) 2-dns server from domain controL(nslookup work fine in exchange 2007 for internet domain Exam Yahoo Hotmail Gmail) 3-mx recorded work fine i can receive email from outside This is my network diagram exchange10.14.0.201-------DC10.14.0.200----SW-----isa2006-------DSLRouter Dc act as dns forwarder for exchange 2007 dc and exchange have full access rule from Isa server (all outbound protocol) allowed This is my domain information (example) My local domain dns is (abc.gov.sa) My website (external) is www.abc.gov.sa some one tell me why i can't send mail to out side PS:after i use smtpdiag i get this output for gmail.com and some site work fine i can send (no problem) yahoo.com hotmail.com and some site (i cant send) i get this error ((((((((Expected "220". Server is not accepting connections))))))) (((((((Expected "250". Server rejected the recipient address)))))) Ps: my ip address is not black list ip i check this with many website can some one help methanks

Ok - sounds interesting to me :), lets try the following steps. - what is your connecting IP if i can know?Login to ISA box physically and try to send email using telnet.here is the one of the mx for hotmail.com [ mx3.hotmail.com internet address = 65.55.92.168 ]Start->run->"cmd"telnet 65.55.92.168 25mail from: anything@yourdomain.comrcpt to: anyvalidhotmailid@hotmail.comdatathis is test email.quit.Do you able to get this email ? (Most of the issues, unable to send email to yahoo, hotmail and aol because of the one of your MX/IP is listed in any of the SPAM database which yahoo, hotmail and AOL refering to.Enableloggin on SMTP traffic on ISA and let us know the progress.Arun Kumar | MCSE - 2K3 + Messaging | ITIL-F V3

Issue description: Mail cant be sent to some domains externally Check info: 1. Yes, please try to use telnet as Arun suggested 2. Whats the windows server version for exchange server? 3. Is there any NDR generated if the message has failed to deliver? 4. Please use message tracking to monitor the test message, see the NDR is generated on which server. If the test mail stuck in the queue, please use queue viewer to check the message 5. Please use Mail Flow Troubleshooter to troubleshoot the issue, its a great troubleshooting tool 6. Please also run ExBPA for a health check

Ijust call isp they create RDNS for me and every thing work finethis is the right solutionthanks