ns record problem

[Alex Tang]

Hi all
Sometimes I cannot send email to a domain and find out the problem may
be caused by some dns setting of the domain.
ref:
my bind version is bind 8.37 and bind 9, and sendmail 

I have a interest porblem about resolve result of ns record.
A domain aplus-beto.com.tw whois authoritative name server are:


      aplus-beto.com.tw            211.23.229.58
      www.aplus-beto.com.tw        211.23.229.58
      mail.aplus-beto.com.tw       211.23.229.58
      ftp.aplus-beto.com.tw        211.23.229.58
which are check by TWNIC

=================================================================
At the first query, I can qery the full ns name (host.domain) of the
domain

Non-authoritative answer:
aplus-beto.com.tw       MX preference = 10, mail exchanger =
ibmserver.aplus-bet
o.com.tw

aplus-beto.com.tw       nameserver = ftp.aplus-beto.com.tw
aplus-beto.com.tw       nameserver = www.aplus-beto.com.tw
aplus-beto.com.tw       nameserver = mail.aplus-beto.com.tw
aplus-beto.com.tw       nameserver = aplus-beto.com.tw
ibmserver.aplus-beto.com.tw     internet address = 211.23.229.58
www.aplus-beto.com.tw   internet address = 211.23.229.58
aplus-beto.com.tw       internet address = 211.23.229.58
==================================================================

However, when I query the ns record, the result become that ns = host

Non-authoritative answer:
aplus-beto.com.tw       MX preference = 10, mail exchanger =
ibmserver.aplus-bet
o.com.tw
aplus-beto.com.tw       nameserver = ibmserver

aplus-beto.com.tw       nameserver = ibmserver

==================================================================

And I found out that is the zone setting which is stored at the dns
server of aplus-beto.com.tw
> server aplus-beto.com.tw
Default Server:  aplus-beto.com.tw
Address:  211.23.229.58
> set q=ns
> aplus-beto.com.tw.
Server:  aplus-beto.com.tw
Address:  211.23.229.58

aplus-beto.com.tw       nameserver = ibmserver
>
=====================================================================
Would any body tell me that it is correct ? When my name server query
that result, my email server cannot send email to that domain.
On the other hand, I use a older version of bind may be 8.1 to query
the domain but result is always positive.
Non-authoritative answer:
aplus-beto.com.tw       nameserver = mail.aplus-beto.com.tw
aplus-beto.com.tw       nameserver = aplus-beto.com.tw
aplus-beto.com.tw       nameserver = ftp.aplus-beto.com.tw
aplus-beto.com.tw       nameserver = www.aplus-beto.com.tw

mail.aplus-beto.com.tw  internet address = 211.23.229.58
aplus-beto.com.tw       internet address = 211.23.229.58
ftp.aplus-beto.com.tw   internet address = 211.23.229.58
www.aplus-beto.com.tw   internet address = 211.23.229.58

Anybody can explain to me and any rfc to explain the formal setting of
name server record ?