fight against spam

Hi, I have configured local dns resolver for proxmox mail gateway by verifying the below post and it is working perfect. Meanwhile while checking logs I could see spam emails still comes, In my analysis it happens as dns cache gets cleared and updated every 24 hours...

Hi, We have two proxmox antispam gateway servers in production, Both are configured to have DNSBL block list with "sbl.spamhaus.org;xbl.spamhaus.org;zen.spamhaus.org" , Grey listing spam protection are also enabled. Now known spammers are already blocked. Meanwhile our users are getting...