[Microsoft.SqlServer.Server.SqlTrigger(Name = "trgclr_update", Target = "table", Event = "AFTER UPDATE")]
    public static void trgclr_update()
    {
        string cmd = "UPD";
        StringBuilder sb = new StringBuilder();
        SqlDataReader reader;
        SqlCommand command;
        DataTable dt = new DataTable();

        if (SqlContext.TriggerContext.TriggerAction == TriggerAction.Update)
        {
            using (SqlConnection conn = new SqlConnection("context connection=true"))
            {
                conn.Open();
                //набор записей обработанных в тригере
                command = new SqlCommand("select RowId from inserted", conn);
                reader = command.ExecuteReader();
                dt.Load(reader);
                reader.Close();
                if (dt.Rows.Count > 0)
                {
                    foreach (DataRow dr in dt.Rows)
                        sb.Append("<Id>" + dr["RowId"].ToString() + "</Id>");

                    //подключенные клиенты
                    command = new SqlCommand(@"SELECT distinct CASE WHEN dmec.client_net_address='<local machine>' Then '127.0.0.1' Else dmec.client_net_address End IPadr
                                                                        FROM sys.sysprocesses sp 
                                                                        INNER JOIN sys.dm_exec_connections dmec ON sp.spid = dmec.session_id
                                                                        WHERE sp.dbid=DB_ID(N'test')", conn);
                    reader = command.ExecuteReader();
                    dt = new DataTable();
                    dt.Load(reader);
                    reader.Close();
                    //отправка сообщений
                    foreach (DataRow dr in dt.Rows)
                        SendMsg(dr["IPadr"].ToString(), string.Format("<{0}>{1}</{0}>", cmd, sb.ToString()));
                }

            }
        }
    }

    private static void SendMsg(string adr, string Msg)
    {
        UdpClient sender = new UdpClient();
        IPEndPoint endPoint = new IPEndPoint(IPAddress.Parse(adr), 49500);

        byte[] bytes = Encoding.UTF8.GetBytes(Msg.ToString());
        try
        {
            sender.Send(bytes, bytes.Length, endPoint);
        }
        finally
        {
            sender.Close();
        }
    }