Dyndns is so nice!1.KeyGen:#dnssec-keygen -a HMAC-MD5 -b 128 -n HOST ddns-keyKddns-key.+157+17069.keyKddns-key.+157+17069.private2.Configure bind name.conf.local. add blow lines:key ddns-key { algorithm HMAC-MD5.SIG-ALG.REG.INT; secret “[key in public file]";};zone “example.com” { … allow-update { key ddns-key; };};3.Use public key to update zone filensupdate -v << EOFserver ns1.example.comkey ddns-key [key in public file]zone example.com.update delete test.example.com. 300 Aupdate add test.example.com. 300 A 192.168.0.22showsendEOF