Can't update peer IP in IAX2 trunk


I have two asterisk 1.4 servers connected via an IAX2 trunk. One of the servers has dynamic DNS service, but when the IP address changes its peer is unable to update the IP address until I restart the asterisk service. Please note that the Linux box hosting asterisk can ping the peer with the new IP address while asterisk is still trying to connect to the old IP. So, it’s not a Linux or dyndns issue since the OS know what the new IP address is but asteirisk does not. Is there any way to change the configuration to solve this problem?