proper dns? we have 2 servers... one for www and mail

[jroe]

ok we have two dns servers... one for our internal use ... and its used by our smtp smartermail email server, hosted on a machine called CITRIX. the mail server is ETP. the web server is ITP and it also hosts are DNS server for external uses and updates (not used by internal or our mail server).

1. citrix.. hosts dns servers for internal use
2. etp hosts email server
3. itp hosts web IIS and dns external..

CITRIX- internal dns settings for cleanhound.com

(same as parent folder) - MX [10] etp.cleanhound.com
(same as parent folder) NS citrix.etradepress.com
(same as parent folder) Start of Authority (SOA)... [13] citrix.etradepress.com., admin.etradepress.com.

etp Host (A) 192.168.100.50 (this is the ip for the mail server hosted on ETP)
itradepress Host (A) 192.168.100.46 (IP for web server hosted on ITP)
mail Alias (CNAME) etp.cleanhound.com.
www Alias (CNAME) itradepress.cleanhound.com

****************************************
ITP ... external dns server... for cleanhound.com settings (not used by our mail we use citrix aka 192.168.100.8)

(same as parent folder) Host(A) 207.250.223.50
(same as parent folder) MX [10] etp.cleanhound.com
(same as parent folder) NS itp.tradepress.com (remeber ITP is web server)
(same as parent folder) NS ns1.milw.twtelecom.net (our ISP)
(same as parent folder) SOA ... [2006101906], itp.tradepress.com., admin.tradepress.com.
(same as parent folder) Text (TXT) v=spf1 mx ptr ip4:207.250.23.0/32 -all
etp Host (A) 207.250.223.50 (external ip address for mail server)
itp Host(A) 207.250.223.46
mail Alias(CNAME) etp.cleanhound.com
www Alias (CNAME) itp.cleanhound.com

Now we use 192.168.100.8 (the internal citrix server) for our internal dns and smtp delivery... is that ok for smtp email? or should we really be using the external dns server? are these settings good/bad or would they lead to performance issues? thanks!