pulin@plpcb-fpc.com这是什么邮箱呀

根据域名的MX解析查到用是263的邮箱。至于你想知道那个账号是什么人用的，得直接问他们公司或本人了。

C:\Documents and Settings\Administrator>nslookup -qt=mx plpcb-fpc.com
*** Can't find server name for address 192.168.0.1: Non-existent domain
*** Default servers are not available
Server: UnKnown
Address: 192.168.0.1

Non-authoritative answer:
plpcb-fpc.com MX preference = 1, mail exchanger = mx01.263xmail.com

mx01.263xmail.com internet address = 211.157.128.31
mx01.263xmail.com internet address = 211.157.128.32
mx01.263xmail.com internet address = 211.157.128.33
mx01.263xmail.com internet address = 211.157.224.130
mx01.263xmail.com internet address = 211.157.224.131
mx01.263xmail.com internet address = 211.150.100.31
mx01.263xmail.com internet address = 211.150.100.32
mx01.263xmail.com internet address = 211.150.100.34
mx01.263xmail.com internet address = 211.150.1