How Can I Work Around DNS Settings in ListManager?

ListManager includes its own DNS resolver optimized to perform at the high speeds ListManager requires to send mail out quickly. Your network environment may be such that you must change the DNS resolver's default settings.

DNS Ports

The DNS resolver initiates the transaction on a random source port between 1024 and 65536 to port 53 on DNS nameservers, and the data returns to the (random) source port. Most firewalls can keep state appropriately - they recognize that the request was initiated internally, and allow the inbound connection on the higher port. However, your firewall may need some additional rules to permit DNS information to be returned correctly to ListManager. Administrators concerned about having higher ports available in their firewall may specify the port settings for the DNS binding through the administrator interface.

Internal DNS Routing

ListManager uses external DNS information for sending mail to your domain, which can cause problems with some firewalls. Instead of delivering to the internal IP address, ListManager uses the external DNS information for your domain, requiring the mail to go out through the firewall and then back in again. If your firewall refuses this kind of traffic, use DNS Bypass to specify how ListManager should route mail correctly inside your firewall.

Alternate DNS Resolver

Administrators may specify an alternate DNS from the one packaged and used by ListManager. Lyris does not recommend specifying an alternative DNS server. Lyris strongly recommends that you use the integrated DNS resolver built into ListManager. If your organization's policy requires use of your own DNS server, understand that Lyris cannot guarantee the standard high-speed and highly accurate ListManager performance. Lyris provides only limited technical support for alternate DNS configurations.

If you understand these conditions and still need to use your own DNS resolver, run an SQL command to insert the DNSServer key into the lyrConfigClusterSettings table (queries may be run from the Administrators's interface within ListManager). For example, to specify an alternate DNS server with the IP address 192.168.223.125, run the following SQL query:

update lyrConfigClusterSettings set DNSServer='192.168.223.125'

ListManager must be restarted for this change to take effect.