|
public Query ( string queryText, QTYPE queryType ) : |
||
| queryText | string | Query text. It depends on queryType. |
| queryType | QTYPE | Query type. |
| return | ||
//-------------------------------------------------------------------------------------------
private string LookupA(string recordname, string sectiontext)
{
Dns_Client dc = new LumiSoft.Net.Dns.Client.Dns_Client();
DnsServerResponse dsr = null;
try
{
dsr = dc.Query(recordname, LumiSoft.Net.Dns.Client.QTYPE.A);
}
catch (Exception ex)
{
throw new Exception("DNS A record query for " + recordname + " failed.", ex);
}
DNS_rr_A[] records = dsr.GetARecords();
string response = sectiontext;
if (records.Length < 1)
{
fail = true;
}
for (int i = 0; i < records.Length; i++)
{
response += (i + 1) + ". ";
response += records[i].IP + " with a TTL of " + records[i].TTL + "<br>";
response += CheckPort(records[i].IP.ToString(), 5222);
response += CheckPort(records[i].IP.ToString(), 5223);
response += CheckPort(records[i].IP.ToString(), 5269);
response += CheckPort(records[i].IP.ToString(), 5270);
}
return(response);
}
/// <summary>
/// Filters sender.
/// </summary>
/// <param name="from">Sender.</param>
/// <param name="api">Reference to server API.</param>
/// <param name="session">Reference to SMTP session.</param>
/// <param name="errorText">Filtering error text what is returned to client. ASCII text, 100 chars maximum.</param>
/// <returns>Returns true if sender is ok or false if rejected.</returns>
public bool Filter(string from,IMailServerApi api,SMTP_Session session,out string errorText)
{
errorText = "";
string ip = session.RemoteEndPoint.Address.ToString();
Dns_Client dns = new Dns_Client();
bool ok = false;
// Don't check PTR for authenticated session and LAN IP ranges
if(session.Authenticated || ip.StartsWith("127.0.0.1") || ip.StartsWith("10.") || ip.StartsWith("192.168")){
return true;
}
DnsServerResponse reponse = dns.Query(ip,QTYPE.PTR);
if(reponse.ResponseCode == RCODE.NO_ERROR){
foreach(PTR_Record rec in reponse.GetPTRRecords()){
if(rec.DomainName.ToLower() == session.EhloName.ToLower()){
ok = true;
break;
}
}
}
if(!ok){
errorText = "Bad EHLO/HELO name, you must have valid DNS PTR record for your EHLO name and IP.";
}
return ok;
}
//-------------------------------------------------------------------------------------------
private string LookupSRV(string recordname, string domain, string sectiontext)
{
recordname += domain;
Dns_Client dc = new LumiSoft.Net.Dns.Client.Dns_Client();
DnsServerResponse dsr = null;
try
{
dsr = dc.Query(recordname, LumiSoft.Net.Dns.Client.QTYPE.SRV);
}
catch (Exception ex)
{
return("<span style='color:red'>DNS SRV record query for " + recordname + domain + " timed out.</span>");
}
DNS_rr_SRV[] records = dsr.GetSRVRecords();
string response = sectiontext;
if (records.Length < 1)
{
fail = true;
}
for (int i = 0; i < records.Length; i++)
{
DnsServerResponse dsr2;
try
{
dsr2 = dc.Query(records[i].Target, QTYPE.A);
}
catch (Exception ex)
{
throw new Exception("DNS sub A record query for " + domain + " failed.", ex);
}
DNS_rr_A[] aRecs = dsr2.GetARecords();
response += (i + 1) + ". ";
response += records[i].Target + " on port " + records[i].Port + " with a TTL of " + records[i].TTL + " and a priority of " + records[i].Priority + "<br />";
for (int x = 0; x < aRecs.Length; x++)
{
response += " ----> Resolves to " + aRecs[x].IP + "<br />";
response += CheckPort(aRecs[x].IP, records[i].Port);
response += CheckPort(aRecs[x].IP, 5223);
}
}
return(response);
}
/// <summary>
/// Resolves host name to IP addresses.
/// </summary>
/// <param name="host">Host name or IP address.</param>
/// <returns>Return specified host IP addresses.</returns>
/// <exception cref="ArgumentNullException">Is raised when <b>host</b> is null.</exception>
public static IPAddress[] Resolve(string host)
{
if (host == null)
{
throw new ArgumentNullException("host");
}
// If hostName_IP is IP
try{
return(new IPAddress[] { IPAddress.Parse(host) });
}
catch {
}
// This is probably NetBios name
if (host.IndexOf(".") == -1)
{
return(System.Net.Dns.GetHostEntry(host).AddressList);
}
else
{
// hostName_IP must be host name, try to resolve it's IP
Dns_Client dns = new Dns_Client();
DnsServerResponse resp = dns.Query(host, QTYPE.A);
if (resp.ResponseCode == RCODE.NO_ERROR)
{
DNS_rr_A[] records = resp.GetARecords();
IPAddress[] retVal = new IPAddress[records.Length];
for (int i = 0; i < records.Length; i++)
{
retVal[i] = records[i].IP;
}
return(retVal);
}
else
{
throw new Exception(resp.ResponseCode.ToString());
}
}
}
/// <summary>
/// Resolves host name to IP addresses.
/// </summary>
/// <param name="host">Host name or IP address.</param>
/// <returns>Return specified host IP addresses.</returns>
/// <exception cref="ArgumentNullException">Is raised when <b>host</b> is null.</exception>
public static IPAddress[] Resolve(string host)
{
if(host == null){
throw new ArgumentNullException("host");
}
// If hostName_IP is IP
try{
return new IPAddress[]{IPAddress.Parse(host)};
}
catch{
}
// This is probably NetBios name
if(host.IndexOf(".") == -1){
return System.Net.Dns.GetHostEntry(host).AddressList;
}
else{
// hostName_IP must be host name, try to resolve it's IP
Dns_Client dns = new Dns_Client();
DnsServerResponse resp = dns.Query(host,QTYPE.A);
if(resp.ResponseCode == RCODE.NO_ERROR){
DNS_rr_A[] records = resp.GetARecords();
IPAddress[] retVal = new IPAddress[records.Length];
for(int i=0;i<records.Length;i++){
retVal[i] = records[i].IP;
}
return retVal;
}
else{
throw new Exception(resp.ResponseCode.ToString());
}
}
}
/// <summary>
/// Filters sender.
/// </summary>
/// <param name="from">Sender.</param>
/// <param name="api">Reference to server API.</param>
/// <param name="session">Reference to SMTP session.</param>
/// <param name="errorText">Filtering error text what is returned to client. ASCII text, 100 chars maximum.</param>
/// <returns>Returns true if sender is ok or false if rejected.</returns>
public bool Filter(string from,IMailServerApi api,SMTP_Session session,out string errorText)
{
errorText = null;
bool ok = true;
// Don't check authenticated users or LAN IP
if(session.Authenticated || IsPrivateIP(session.RemoteEndPoint.Address)){
return true;
}
try{
//--- Load data -----------------------
DataSet ds = new DataSet();
ds.Tables.Add("General");
ds.Tables["General"].Columns.Add("CheckHelo");
ds.Tables.Add("BlackListSettings");
ds.Tables["BlackListSettings"].Columns.Add("ErrorText");
ds.Tables.Add("BlackList");
ds.Tables["BlackList"].Columns.Add("IP");
ds.Tables.Add("Servers");
ds.Tables["Servers"].Columns.Add("Cost");
ds.Tables["Servers"].Columns.Add("Server");
ds.Tables["Servers"].Columns.Add("DefaultRejectionText");
ds.ReadXml(Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location) + "\\lsDNSBL_Filter_db.xml");
Dns_Client dns = new Dns_Client();
#region General
if(ds.Tables["General"].Rows.Count == 1){
if(Convert.ToBoolean(ds.Tables["General"].Rows[0]["CheckHelo"])){
DnsServerResponse response = dns.Query(session.EhloName,QTYPE.A);
// If dns server connection errors, don't block.
if(response.ConnectionOk && response.ResponseCode != RCODE.SERVER_FAILURE){
bool found = false;
foreach(A_Record a in response.GetARecords()){
if(session.RemoteEndPoint.Address.ToString() == a.IP){
found = true;
break;
}
}
if(!found){
errorText = "Not valid DNS EHLO/HELO name '" + session.EhloName + "' !";
return false;
}
}
}
}
#endregion
#region Balck List
foreach (DataRow dr in ds.Tables["BlackList"].Rows){
if(IsAstericMatch(dr["IP"].ToString(),session.RemoteEndPoint.Address.ToString())){
errorText = ds.Tables["BlackListSettings"].Rows[0]["ErrorText"].ToString();
return false;
}
}
#endregion
#region DNSBL
foreach(DataRow dr in ds.Tables["Servers"].Rows){
DnsServerResponse dnsResponse = dns.Query(ReverseIP(session.RemoteEndPoint.Address) + "." + dr["Server"].ToString(),QTYPE.ANY);
A_Record[] recs = dnsResponse.GetARecords();
if(recs.Length > 0){
// Logging blocking
WriteFilterLog("Sender:" + from + " IP:" + session.RemoteEndPoint.Address.ToString() + " blocked\r\n");
errorText = dr["DefaultRejectionText"].ToString();
// Server provided return text, use it
if(dnsResponse.GetTXTRecords().Length > 0){
errorText = dnsResponse.GetTXTRecords()[0].Text;
}
if(errorText == ""){
errorText = "You are in '" + dr["Server"].ToString() + "' rejection list !";
}
return false;
}
}
#endregion
}
catch{
}
return ok;
}
private void m_pTestDns_Click(object sender, EventArgs e)
{
Dns_Client.DnsServers = new string[]{m_pDns1.Text};
Dns_Client.UseDnsCache = false;
Dns_Client dns = new Dns_Client();
DnsServerResponse response = dns.Query("lumisoft.ee",QTYPE.MX);
if(!response.ConnectionOk || response.ResponseCode != RCODE.NO_ERROR){
MessageBox.Show(this,"Invalid dns server(" + m_pDns1.Text + "), can't resolve lumisoft.ee","Info",MessageBoxButtons.OK,MessageBoxIcon.Warning);
return;
}
Dns_Client.DnsServers = new string[]{m_pDns2.Text};
Dns_Client.UseDnsCache = false;
Dns_Client dns2 = new Dns_Client();
response = dns2.Query("lumisoft.ee",QTYPE.MX);
if(!response.ConnectionOk || response.ResponseCode != RCODE.NO_ERROR){
MessageBox.Show(this,"Invalid dns server(" + m_pDns2.Text + "), can't resolve lumisoft.ee","Info",MessageBoxButtons.OK,MessageBoxIcon.Warning);
return;
}
MessageBox.Show(this,"Ok.","Info",MessageBoxButtons.OK,MessageBoxIcon.Information);
}
/// <summary>
/// Gets specified email domain SMTP hosts. Values are in descending priority order.
/// </summary>
/// <param name="domain">Domain name. This value can be email address too, then domain parsed automatically.</param>
/// <returns>Returns specified email domain SMTP hosts.</returns>
/// <exception cref="ArgumentNullException">Is raised when <b>domain</b> is null.</exception>
/// <exception cref="ArgumentException">Is raised when any of the arguments has invalid value.</exception>
/// <exception cref="DNS_ClientException">Is raised when DNS query failure.</exception>
public static string[] GetDomainHosts(string domain)
{
if(domain == null){
throw new ArgumentNullException("domain");
}
if(string.IsNullOrEmpty(domain)){
throw new ArgumentException("Invalid argument 'domain' value, you need to specify domain value.");
}
// We have email address, parse domain.
if(domain.IndexOf("@") > -1){
domain = domain.Substring(domain.IndexOf('@') + 1);
}
List<string> retVal = new List<string>();
// Get MX records.
Dns_Client dns = new Dns_Client();
DnsServerResponse response = dns.Query(domain,QTYPE.MX);
if(response.ResponseCode == RCODE.NO_ERROR){
foreach(DNS_rr_MX mx in response.GetMXRecords()){
// Block invalid MX records.
if(!string.IsNullOrEmpty(mx.Host)){
retVal.Add(mx.Host);
}
}
}
else{
throw new DNS_ClientException(response.ResponseCode);
}
/* RFC 2821 5.
If no MX records are found, but an A RR is found, the A RR is treated as if it
was associated with an implicit MX RR, with a preference of 0, pointing to that host.
*/
if(retVal.Count == 0){
retVal.Add(domain);
}
return retVal.ToArray();
}
//-------------------------------------------------------------------------------------------
private string LookupSRV(string recordname, string domain, string sectiontext)
{
recordname += domain;
Dns_Client dc = new LumiSoft.Net.Dns.Client.Dns_Client();
DnsServerResponse dsr = null;
try
{
dsr = dc.Query(recordname, LumiSoft.Net.Dns.Client.QTYPE.SRV);
}
catch (Exception ex)
{
return "<span style='color:red'>DNS SRV record query for " + recordname + domain + " timed out.</span>";
}
DNS_rr_SRV[] records = dsr.GetSRVRecords();
string response = sectiontext;
if (records.Length < 1)
fail = true;
for (int i = 0; i < records.Length; i++)
{
DnsServerResponse dsr2;
try
{
dsr2 = dc.Query(records[i].Target, QTYPE.A);
}
catch (Exception ex)
{
throw new Exception("DNS sub A record query for " + domain + " failed.", ex);
}
DNS_rr_A[] aRecs = dsr2.GetARecords();
response += (i + 1) + ". ";
response += records[i].Target + " on port " + records[i].Port + " with a TTL of " + records[i].TTL + " and a priority of " + records[i].Priority + "<br />";
for (int x = 0; x < aRecs.Length; x++)
{
response += " ----> Resolves to " + aRecs[x].IP + "<br />";
response += CheckPort(aRecs[x].IP, records[i].Port);
response += CheckPort(aRecs[x].IP, 5223);
}
}
return response;
}
//-------------------------------------------------------------------------------------------
private string LookupA(string recordname, string sectiontext)
{
Dns_Client dc = new LumiSoft.Net.Dns.Client.Dns_Client();
DnsServerResponse dsr = null;
try
{
dsr = dc.Query(recordname, LumiSoft.Net.Dns.Client.QTYPE.A);
}
catch (Exception ex)
{
throw new Exception("DNS A record query for " + recordname + " failed.", ex);
}
DNS_rr_A[] records = dsr.GetARecords();
string response = sectiontext;
if (records.Length < 1)
fail = true;
for (int i = 0; i < records.Length; i++)
{
response += (i + 1) + ". ";
response += records[i].IP + " with a TTL of " + records[i].TTL + "<br>";
response += CheckPort(records[i].IP.ToString(), 5222);
response += CheckPort(records[i].IP.ToString(), 5223);
response += CheckPort(records[i].IP.ToString(), 5269);
response += CheckPort(records[i].IP.ToString(), 5270);
}
return response;
}
