Netease Mail server's IPs are:
    202.106.186.34
    202.108.36.[195-254]
    202.108.5.[1-254]
    202.108.9.[128-254]
    220.181.12.[1-254]
    220.181.13.[1-254]
    220.181.14.[1-254]
    220.181.15.[1-254]
    220.181.28.149
    Netease Mail's domains include:163.com,126.com,188.com,vip.163.com,yeah.net,
netease.com, corp.netease.com,service.netease.com

    Please note that:All these domains are possibly crossing among several IP ranges.There are not strict mapping between IPs and domains.