nanog mailing list archives

Re: Email Server and DNS


From: TR Shaw <tshaw () oitc com>
Date: Sun, 3 Nov 2013 13:10:33 -0500

In addition to all the other reco's below, 

1) only allow sending by your users from the submit port and only with authentication. There should be no client 
sending through the SMTP port.

2) Implement SSL on POP & IMAP if at all possible Otherwise enforce CRAM-MD5

3) Review logs esp pop and imap login failures. 

4) Turn off VRFY. 

On Nov 3, 2013, at 11:49 AM, Private Sender wrote:

Signed PGP part
On 11/3/2013 8:39 AM, rwebb () ropeguru com wrote:
So I figured a little break from the NSA was in order.

I am looking for some info on current practice for an email server 
and SMTP delivery. It has been a while since I have had to setup an
email server and I have been tasked with setting up a small one for
a friend. My question centers around the server sending outgoing
email and the current practices requirements for other servers to
accept email Things like rDNS, SPF records, etc...

I am pretty much set on the issue of incoming spam and virus. 
Probably overkill but it is checked at the Sophos UTM firewall and 
at the email server itself.

Thanks,

Robert


MX, PTR, and SPF are really all you need. I would recommend you go a
step further and use DKIM, ADSP, and DMARC. It will help keep asshat
spammers from flaming your domain all over the internet.

I use http://www.unlocktheinbox.com/ to verify my configuration.

- -- 
- -Bret Taylor



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