On 2016-07-28 11:07, Roger Goh wrote:
If the IP address is spoofed, how does firewall rejects it?In the case of MS Exchange, will implementing something like SPF (Sender Policy Framework) and Sender ID filtering help?
no, if postfix see local sender domains on port 25 it should reject it all else will fail ips does not materSender-ID is depricated, dont added it, but if you like spf could help if added to each sender domain carefully