mails mark as spam why?

Hello everyone,

I have a few web sites and set them up with Virtualmin on the same server. When I try to send mail from some of my websites, receiver’s mail systems (such as hotmail, yahoo and some companies, universities) mark my mails as spam. I created all the records they requested for hotmail & yahoo but still same. I have the same record on my main web site and I don’t have any problem with it. The weird thing is the configuration is the same for all. I just wanted to learn if I created the correct dns records for the sites so I will post it here and waiting for some advices & helps. Thanks in advance.

PS: domain1.com & ip address just for example


BIND DNS Master Zone:

$ttl 38400
@ IN SOA ns1.domain1.com. root.ns1.domain1.com. (
2009120906
10800
3600
604800
38400 )
@ IN NS ns1.domain1.com.
domain1.com. IN A 213.113.100.111
www.domain1.com. IN A 213.113.100.111
localhost.domain1.com. IN A 127.0.0.1
mail.domain1.com. IN A 213.113.100.111
domain1.com. IN MX 5 mail.domain1.com.
domain1.com. IN TXT “v=spf1 a mx ptr ip4:213.113.100.111 include:mail.domain1 ~all”
213.113.100.111.domain1.com. IN PTR domain1.com.
213.113.100.111.domain1.com. IN PTR mail.domain1.com

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