Why does GMS Mail report 'Loop Detected'?
From time to time you may find messages stored in the BadMes directory on your GMS server. One reason that this can happen is that the mail has been looping through the server until it has reached the "hop count" you have specified, i.e. it has passed through the server the same number of times as the hop count limit.
This is typically caused by a mis-configuration of the domain aliases on the server which causes the server to assume that an address is local when it is not. Take the following example….
A company is running two mail servers, the first of these handles all incoming and outgoing mail for the company. The second handles mail for a specific department within the company which we shall call "dept", mail is forwarded on from Server1 to Server2 by means of specific forward accounts.
The Server1 has been set up to serve mail for a domain company.dom. when setting up the domain a domain alias of *.company.dom is automatically added to the configuration. This means that Server1 will accept mail for the domain company.dom and all of its sub domains. Server2 has been set up to serve mail for a domain dept.company.dom.
User1 on Server1 actually works in "dept" so he sets up a forward account for himself on Server1 that forwards all mail coming in to his account on to the appropriate account on Server2, i.e. all mail is forwarded on to User1@dept.company.dom
This is where the problem arises. As Server1 has been configured with a domain alias of *.company.dom it assumes that User1@dept.company.dom is local to itself. Therefore the mail goes back into the account for User1 on Server1, this mail is again forwarded on to User1@dept.company.dom and so on, until the hop count is reached.
Removing the Domain Alias of *.company.dom will allow this configuration to function correctly.