`https://www.ovh.com/nic/update?system=dyndns&hostname=$HOSTNAME`
currently if an ISP changes server's public IP address while a server is down,someone who gets the IP may gain unwanted access to dyndns subdomain.
there is a need for a parameter which would allow to set myip expiration time.
after expiration the dyndns ip addr could change to 0.0.0.0 or there could be some option,parameter to set backup address, backup cname.
`https://www.ovh.com/nic/update?system=dyndns&hostname=$HOSTNAME&expiry=15m&backupip=MYIP2`
`https://www.ovh.com/nic/update?system=dyndns&hostname=$HOSTNAME&expiry=15h`