申请好changeip用户名，密码，域名，对应修改下面的脚本后即可使用：

# EDIT YOUR DETAILS / CONFIGURATION HERE（这里更改用户配置）
# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
:global ddnsuser "YourChangeIPUserID"
:global ddnspass "PASSWORD"
:global ddnshost "MyRouterHostname.example.org"
:global ddnsinterface "pppoe-out1"
# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# END OF USER DEFINED CONFIGURATION（用户配置更改结束，下面的命令不要动）
# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
:global ddnssystem ("mt-" . [/system package get [/system package find name=system] version] )
:global ddnsip [ /ip address get [/ip address find interface=$ddnsinterface] address ]
:global ddnslastip
:if ([:len [/interface find name=$ddnsinterface]] = 0 ) do={ :log info "DDNS: No interface named $ddnsinterface, please check configuration." }
:if ([ :typeof $ddnslastip ] = "nothing" ) do={ :global ddnslastip 0.0.0.0/0 }
:if ([ :typeof $ddnsip ] = "nothing" ) do={
:log info ("DDNS: No ip address present on " . $ddnsinterface . ", please check.")
} else={
:if ($ddnsip != $ddnslastip) do={
:log info "DDNS: Sending UPDATE!"
:log info [ :put [/tool dns-update name=$ddnshost address=[:pick $ddnsip 0 [:find $ddnsip "/"] ] key-name=$ddnsuser key=$ddnspass ] ]
:global ddnslastip $ddnsip
} else={
:log info "DDNS: No changes necessary."
}
}
# END OF SCRIPT

log: