Sendmail 寄信太慢

Sendmail gethostbyaddr error

Disable DNS Lookup

/etc/mail/sendmail.cf
#O ServiceSwitchFile=/etc/mail/service.switch
註解移除 =>
O ServiceSwitchFile=/etc/mail/service.switch


/etc/mail/service.switch
hosts files
aliases files

補充一:如果要關閉的話, 得移除/etc/mail/service.switch

補充二:
另一種設定方式

hosts dns files
aliases files