开始--运行--cmd 
nslookup -qe=mx ebadu.net 
正确指示: 
C:\Documents and Settings\Administrator>nslookup -qe=mx ebadu.net 
Server: ns.ahhfptt.net.cn 
Address: 202.102.192.68 
DNS request timed out. 
timeout was 2 seconds. 
Non-authoritative answer: 
ebadu.net MX preference = 0, mail exchanger = mail.ebadu.net 
ebadu.net nameserver = ns2.dns.com.cn 
ebadu.net nameserver = ns1.dns.com.cn 
mail.ebadu.net internet address = 222.186.12.16 
ns1.dns.com.cn internet address = 122.70.138.5 
ns1.dns.com.cn internet address = 122.70.138.6 
ns1.dns.com.cn internet address = 124.42.122.8 
ns1.dns.com.cn internet address = 124.42.122.9 
ns2.dns.com.cn internet address = 124.42.122.5 
ns2.dns.com.cn internet address = 124.42.122.6 
ns2.dns.com.cn internet address = 122.70.138.8 
ns2.dns.com.cn internet address = 122.70.138.9 
见到NS记录显示了IP 即为通畅状态
nslookup -qe=mx ebadu.com
C:\Documents and Settings\Administrator>nslookup -qe=mx ebadu.com 
Server: ns.ahhfptt.net.cn 
Address: 202.102.192.68 
DNS request timed out. 
timeout was 2 seconds. 
Non-authoritative answer: 
ebadu.com canonical name =  
ebadu.net 
primary name server = ns2.dns.com.cn 
responsible mail addr = root.ns2.dns.com.cn 
serial = 2008061113 
refresh = 3600 (1 hour) 
retry = 3600 (1 hour) 
expire = 68400 (19 hours) 
default TTL = 180 (3 mins) 
反馈不回NSIP记录.即为不通状态! 
检测反解析是否成功 
nslookup –qt=ptr 61.191.191.182 
返回信息如下: 
C:\Documents and Settings\user>nslookup –qt=ptr 61.192.56.23 
Server: mx.diyway.net 
Address: 61.192.56.23 
说明这个IP的反解析就是成功了。 
返回信息如下 
C:\Documents and Settings\user>nslookup –qt=ptr 61.192.56.23 
*** Can't find server name for address 61.142.80.154: Non-existent domain 
Server: UnKnown 
Address: 61.192.56.23 
说明这个IP的反解析没有作。