Implementing SNMP SendTrap using Indy components

Question

I need to report errors from my application on C++Builder via SNMP.

I started implementing SNMP SendTrap using Indy components.

void __fastcall TMainForm::btSendTrapClick(TObject *Sender)
{
UnicodeString myEnterprise   = "1.5.5.5.5.5.5.5";
UnicodeString eventType      = "1.5.5.5.5.5.5.5.1";
UnicodeString eventDistance  = "1.5.5.5.5.5.5.5.2";

TIdSNMP * idSnmp = 0;
TSNMPInfo * infoSnmp = 0;

idSnmp                 = new TIdSNMP(NULL);
infoSnmp               = new TSNMPInfo(idSnmp);

idSnmp->Host           = edHost->Text;
idSnmp->Community      = "public";

infoSnmp->Host           = edHost->Text;
infoSnmp->Community      = "public";
infoSnmp->Enterprise = myEnterprise;
infoSnmp->GenTrap = 6;                       // I've met such values
infoSnmp->SpecTrap = 1;                      // somewhere in inet
infoSnmp->MIBAdd(eventType,"ftCritical");
infoSnmp->MIBAdd(eventDistance,"2.357");

idSnmp->SendTrap();

delete idSnmp;
}

But when I run application there is no udp activity in my system. When I run something like this

idSnmp->QuickSend(sysDescr, "public", edHost->Text, val);

wireshark shows 192.168.100.21 192.168.100.19 SNMP 82 get-request 1.3.6.1.2.1.1.3.0

but when idSnmp->SendTrap() wireshark sees nothing (filter for wireshark is UDP portrange 161-162 in both cases)

I'll be glad to see some remarks about my code or maybe working example of SendTrap :)

Answer 1

You are not populating TIdSNMP::Trap with any values. That is why TIdSNMP::SendTrap() is not sending anything. There is nothing for it to send.

Try this instead:

void __fastcall TMainForm::btSendTrapClick(TObject *Sender)
{
    String myEnterprise   = _D("1.5.5.5.5.5.5.5");
    String eventType      = myEnterprise + _D(".1");
    String eventDistance  = myEnterprise + _D(".2");

    TIdSNMP *idSnmp = new TIdSNMP(NULL);

    idSnmp->Trap->Host       = edHost->Text;
    idSnmp->Trap->Community  = _D("public");
    idSnmp->Trap->Enterprise = myEnterprise;
    idSnmp->Trap->GenTrap    = 6;                       // I've met such values
    idSnmp->Trap->SpecTrap   = 1;                      // somewhere in inet
    idSnmp->Trap->MIBAdd(eventType, _D("ftCritical"));
    idSnmp->Trap->MIBAdd(eventDistance, _D("2.357"));

    idSnmp->SendTrap();

    delete idSnmp;
}

Alternatively, you can use TIdSNMP::QuickSendTrap() instead:

void __fastcall TMainForm::btSendTrapClick(TObject *Sender)
{
    String myEnterprise   = _D("1.5.5.5.5.5.5.5");
    String eventType      = myEnterprise + _D(".1");
    String eventDistance  = myEnterprise + _D(".2");

    TStringList *names = new TStringList;
    names->Add(eventType);
    names->Add(eventDistance);

    TStringList *values = new TStringList;
    values->AddObject(_D("ftCritical"), (TObject*)ASN1_OCTSTR);
    values->AddObject(_D("2.357"), (TObject*)ASN1_OCTSTR);

    TIdSNMP *idSnmp = new TIdSNMP(NULL);
    idSnmp->QuickSendTrap(edHost->Text, myEnterprise, _D("public"), 162, 6, 1, names, values);
    delete idSnmp;

    delete names;
    delete values;
}

Or, if you are compiling for mobile:

void __fastcall TMainForm::btSendTrapClick(TObject *Sender)
{
    String myEnterprise   = _D("1.5.5.5.5.5.5.5");
    String eventType      = myEnterprise + _D(".1");
    String eventDistance  = myEnterprise + _D(".2");

    TIdMIBValueList *mibs = new TIdMIBValueList;
    mibs->Add(TIdMIBValue(eventType, _D("ftCritical"), ASN1_OCTSTR));
    mibs->Add(TIdMIBValue(eventDistance, _D("2.357"), ASN1_OCTSTR));

    TIdSNMP *idSnmp = new TIdSNMP(NULL);
    idSnmp->QuickSendTrap(edHost->Text, myEnterprise, _D("public"), 162, 6, 1, mibs);
    delete idSnmp;

    delete mibs;
}