2 domains

[exmadyn]

i have 2 domains setup in one client with different dns but have shared ip. here are the info:

mydomain1:
72.xx.xx.xxx / 24 PTR mydomain1.com.
ftp.mydomain1.com. CNAME mydomain1.com.
mydomain1.com. NS ns1.mydomain1.com.
mydomain1.com. NS ns2.mydomain1.com.
mydomain1.com. A 72.xx.xx.xxx
mydomain1.com. MX (10) mail.mydomain1.com.
mail.mydomain1.com. A 72.xx.xx.xxx
ns1.mydomain1.com. A 72.xx.xx.xxx
ns2.mydomain1.com. A 72.xx.xx.xxx
webmail.mydomain1.com. A 72.xx.xx.xxx
www.mydomain1.com CNAME mydomain1.com.


mydomain2:
72.xx.xx.xxx / 24 PTR mydomain2.com.
ftp.mydomain2.com. CNAME mydomain2.com.
mydomain2.com. NS ns1.mydomain2.com.
mydomain2.com. NS ns2.mydomain2.com.
mydomain2.com. A 72.xx.xx.xxx
mydomain2.com. MX (10) mail.mydomain2.com.
mail.mydomain2.com. A 72.xx.xx.xxx
ns1.mydomain2.com. A 72.xx.xx.xxx
ns2.mydomain2.com. A 72.xx.xx.xxx
webmail.mydomain2.com. A 72.xx.xx.xxx
www.mydomain2.com. CNAME mydomain2.com.


on the server itself, the dns has the default setting, no entries:
<domain>. NS ns2.<domain>.
<domain>. NS ns1.<domain>.
<domain>. A <ip>
mail.<domain>. A <ip>
ns1.<domain>. A <ip>
ns2.<domain>. A <ip>
webmail.<domain>. A <ip>
ftp.<domain>. CNAME <domain>.
<domain>. MX (10) mail.<domain>.
<ip> / 24 PTR <domain>.

both domain names are registered outside, so i use their nameserver respectively to point to the vps.

at first, when i hit mydomain2.com, it works fine but not for long since it gets redirected to mydomain1.com. what's wrong with this?

also, i can't access the webmail.mydomain2.com, but when is use webmail.mydomain1.com, i can login the info@mydomain2.com. is there a conflict with this?

how to solve these?