Re: [IMail Forum] Non Recursion in DNS and effect on IMail

[Matrosity Hosting]

MS DNS doesn't support recursion for a set of IP's which kinda sucks. In order to avoid someone using your DNS you have to block port 53 with a firewall or use a different DNS. Regards, Bill Ted Daniels wrote: Len: It does. DNS/SelectDNSServer/RightClick/Properties/Advanced/Check Disable Recurion I ran a www.DNSReport.com report on various servers and got a Red Flag on this item as my DNS Server did not have Disable Recursion checked, thus allowing all and sundry to use my DNS server. The idea was to use my DNS server just for my own domains to reduce DNS traffic and stop third parties using our DNS server for proxy DOS attacks. See report (http://www.dnsreport.com/info/opendns.htm) As soon as I did this, IMail accounts stopped receiving e-mails and received message "Could not deliver" when sending. The e-mail accounts were all for domains I was hosting. and I have DNS forwarders identified for domains for which I am not SOA. Could you expand your response a bit - I am not a Unix expert. In fact I fell into providing e-mail services by mistake and now have to manage thousands of them "on the side", as its not my main business and am not a network expert. Ted Daniels ----- Original Message ----- From: "Len Conrad" <[EMAIL PROTECTED]> To: <Imail_Forum@list.ipswitch.com> Sent: Sunday, July 02, 2006 4:11 AM Subject: Re: [IMail Forum] Non Recursion in DNS and effect on IMail I recently checked "No Recursion" in Win2K DNS (Advanced Tab) so that my DNS server would act as DNS only for domains for which my DNS server was SOA in order to deny third parties the ability to use my DNS server for DOS attacks and so on. All users reported that they could no longer send or receive e-mail apart from those sent by other domains for which my DNS server was SOA. Un-check No Recursion and the mail started flowing again. Any way around this? With MS DNS? no, recursion is either on or off. With a firewall, you can leave MS DNS recursion on and block access from internet to port 53. Use DNS like BIND that allows recursion restricted by ACL, eg, for your subnet. Len To Unsubscribe: http://www.ipswitch.com/support/mailing-lists.html List Archive: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ Knowledge Base/FAQ: http://www.ipswitch.com/support/IMail/ To Unsubscribe: http://www.ipswitch.com/support/mailing-lists.html List Archive: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ Knowledge Base/FAQ: http://www.ipswitch.com/support/IMail/