hello, done it! when debugging i could see all the entries in IPGrant, the problem was converting the object array into a string array, i managed this with: ExIpSecurity ipsec = new ExIpSecurity(); ipsec.BindToSmtpVsi(someSMTPserver, 1, "someDC"); ipsec.GetRelayIpList(); object[] o = (object[])ipsec.IPGrant; string[] s = new string[o.Length]; Array arr = s; o.CopyTo(arr, 0); s = (string[])arr; foreach (string i in s) { sw.WriteLine(i); } thanks for your help mate, have a good weekend. Phil