I'm running ISPConfig 2.2.13 on Debian Sarge. I've got several hundred customers/domains running, for the most part smoothly. One of my customers is asking that I modify his MX records to point to a machine other than ISPConfig. We are doing this for several other customers as well - we offer a service called Premium Spam Control, and several of our customers have their e-mail filtered through PSC. When configuring mail this way, we set the MX records to point to rb.<our domain>.com and fr.<our domain>.com. No problem - as I said, we are doing that for several customers. This latest customer, though, is a problem. When I set up an MX record for fr at priority 30, the record is accepted. When I attempt to add an MX record for rb at priority 20, I get an error reading " This or a similar MX Record does already exist in this zone." Examining the MX records for this domain does not show any MX records other than the one pointing to fr. I have emptied the Admin recycle bin and the reseller level recycle bin. I tried looking through the database records, but I haven't yet figured out which tables link the dns_mx table to the other required tables. Can someone document for me how the dns_mx table links to the other tables that get involved here? I'm familiar with tracing info through isp_isp_domain, isp_dep, etc, I'm just not sure what tables to use and what fields tie them together in the case of DNS issues.