Windows 7 x64下奇怪的DNS返回值

C:\Users\aa001>nslookup ww1.sinaimg.cn 8.8.8.8
Server: google-public-dns-a.google.com
Address: 8.8.8.8

Non-authoritative answer:
Name: sinaimg1st.xdwscache.glb0.lxdns.com
Address: 61.155.141.16
Aliases: ww1.sinaimg.cn
ww.sinaimg.lxdns.com
public.sinaimg.005.cnccdn.com

C:\Users\aa001>nslookup ww1.sinaimg.cn 114.114.114.114
Server: public1.114dns.com
Address: 114.114.114.114

Non-authoritative answer:
Name: sinaimg1st.xdwscache.glb0.lxdns.com
Address: 120.39.183.29
Aliases: ww1.sinaimg.cn
weiboimg.gslb.sinaedge.com
weiboimg.grid.sinaedge.com
ww.sinaimg.lxdns.com
public.sinaimg.005.cnccdn.com

C:\Users\aa001>nslookup ww1.sinaimg.cn 218.85.152.99
Server: FJ-DNS.xm.fj.cn
Address: 218.85.152.99

DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
Non-authoritative answer:
Name: weiboimg.grid.sinaedge.com
Address: 110.81.153.220
Aliases: ww1.sinaimg.cn
weiboimg.gslb.sinaedge.com

C:\Users\aa001>nslookup ww1.sinaimg.cn 178.79.131.110
Server: li187-110.members.linode.com
Address: 178.79.131.110

Non-authoritative answer:
Name: ww1.sinaimg.cn.lan
Address: 178.79.131.110

唯独v2ex的dns最后会有一个.lan，地址就是自己。与此同时其他的dns，包括google，114和本地ISP返回都是正常的。