diff --git a/command/agent/agent.go b/command/agent/agent.go
index e6219a1b83..c2394b9a30 100644
--- a/command/agent/agent.go
+++ b/command/agent/agent.go
@@ -604,14 +604,16 @@ func (a *Agent) AddService(service *structs.NodeService, chkTypes CheckTypes, pe
 	// Warn if the service name is incompatible with DNS
 	if !dnsNameRe.MatchString(service.Service) {
 		a.logger.Printf("[WARN] Service name %q will not be discoverable "+
-			"via DNS due to invalid characters", service.Service)
+			"via DNS due to invalid characters. Valid characters include "+
+			"all alpha-numerics and dashes.", service.Service)
 	}
 
 	// Warn if any tags are incompatible with DNS
 	for _, tag := range service.Tags {
 		if !dnsNameRe.MatchString(tag) {
 			a.logger.Printf("[WARN] Service tag %q will not be discoverable "+
-				"via DNS due to invalid characters", tag)
+				"via DNS due to invalid characters. Valid characters include "+
+				"all alpha-numerics and dashes.", tag)
 		}
 	}