步驟:
1.新增Postfix Relay-Nat主機的A紀錄,使DNS是能查詢到Postfix Relay-Nat的A紀錄
relay.demo.com. 86400 IN A 1.2.3.4
relay.demo.com. 86400 IN A 1.2.3.4
2.將要Realy的mail domain MX紀錄對應改為Postfix Relay-Nat
mail.demo.com. 3600 IN MX 20 relay.demo.com.
3.修改/etc/postfix/master.cf,新增定義一個relay-nat的服務
elay-nat unix - - - - - smtp
4.修改/etc/postfix/main.cf,新增允許relay的domain name和傳輸路由表
relay_domains = mail.demo.com #多網域可用“,”隔開
transport_maps = hash:/etc/postfix/transport
5. 編輯/etc/postfix/transport檔案,ip外的[]是指不對ip位址做DNS查詢
mail.demo.com relay-nat:[192.168.1.252]
6.編譯/etc/postfix/transport
$postmap /etc/postfix/transport
7.編譯完會產生資料庫檔:transport.db,可用postmap測試對應
$ postmap -q mail.demo.com transport
relay-nat:[192.168.1.252]
8.重新啟動postfix