Hi Selva, Please refer the following.. Spf Sender Policy Framework (SPF), as defined in RFC 4408, is an e-mail validation system designed to prevent e-mail spam by addressing a common vulnerability, source address spoofing. SPF allows administrators to specify which hosts are allowed to send e-mail from a given domain by creating a specific DNS SPF record in the public DNS. Mail exchangers then use the DNS to check that mail from a given domain is being sent by a host sanctioned by that domain's administrators.[1]
http://en.wikipedia.org/wiki/Sender_Policy_Framework configure spf in dns http://www.cyberciti.biz/faq/howto-bind-djbdns-spf-antispam-dns-configuration/ Configure spf in postfix http://www.howtoforge.com/postfix_spf DomainKeys DomainKeys is an authentication framework which stores public-keys in DNS and digitally signs emails on a domain basis. Domain Keys is an e-mail authentication system designed to verify the DNS domain of an e-mail sender and the message integrity DomainKeys is a spam and phishing scam fighting method which works by signing outbound e-mail messages with a cryptographic signature which can be verified by the recipient to determine if the messages originates from an authorized system. The process of signing outbound messages and verifying this signature is typically done by the e-mail servers at each end - not by end-users client software. DomainKeys uses DNS TXT-records to define DomainKeys policy and public encryption keys for a domain name. DomainKeys is developed and patented by Yahoo!. For details please see http://domainkeys.sourceforge.net/ DKIM is an extension of DomainKeys which uses the same style DNS records. For details see http://www.dkim.org Dkim DKIM is an extension of DomainKeys which uses the same style DNS records. For details see http://www.dkim.org http://en.wikipedia.org/wiki/DomainKeys_Identified_Mail configure Dkim in dns http://www.simpledns.com/kb.aspx?kbid=1092 configure Dkim in Postfix http://www.howtoforge.com/postfix_dkfilter_domain_keys_implementation Dns Providers support TXT http://www.kitterman.com/spf/txt.html B.Sadhiq [Non-text portions of this message have been removed]
