The relative priority of an MX server is determined by the preference number present in the DNS MX record. When a remote client (typically another mail server) does an MX lookup for the domain name, it gets a list of servers and their preference numbers. The MX record with the smallest preference number has the highest priority and is the first server to be tried. The remote client will go

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保持对itjm.com，5ubg.com两大域名的长期持有。itjm.com解析至本博客。5ubg.com则用于经营性活动。