diff --git a/src/Trigger.cc b/src/Trigger.cc
index 164f11b885..b7e08b557e 100644
--- a/src/Trigger.cc
+++ b/src/Trigger.cc
@@ -217,8 +217,15 @@ bool Trigger::Eval()
 			Name());
 
 	Unref(v);
+	v = 0;
 	stmt_flow_type flow;
-	v = body->Exec(f, flow);
+
+	try
+		{
+		v = body->Exec(f, flow);
+		}
+	catch ( InterpreterException& e )
+		{ /* Already reported. */ }
 
 	if ( is_return )
 		{
@@ -300,7 +307,14 @@ void Trigger::Timeout()
 		{
 		stmt_flow_type flow;
 		Frame* f = frame->Clone();
-		Val* v = timeout_stmts->Exec(f, flow);
+		Val* v = 0;
+
+		try
+			{
+			v = timeout_stmts->Exec(f, flow);
+			}
+		catch ( InterpreterException& e )
+			{ /* Already reported. */ }
 
 		if ( is_return )
 			{
@@ -382,7 +396,7 @@ void Trigger::Attach(Trigger *trigger)
 
 void Trigger::Cache(const CallExpr* expr, Val* v)
 	{
-	if ( disabled )
+	if ( disabled || ! v )
 		return;
 
 	ValCache::iterator i = cache.find(expr);
diff --git a/testing/btest/Baseline/core.dns-interpreter-exceptions/out b/testing/btest/Baseline/core.dns-interpreter-exceptions/out
new file mode 100644
index 0000000000..c081edc489
--- /dev/null
+++ b/testing/btest/Baseline/core.dns-interpreter-exceptions/out
@@ -0,0 +1,12 @@
+1300475167.096535 expression error in /Users/jsiwek/Projects/bro/bro/testing/btest/.tmp/core.dns-interpreter-exceptions/dns-interpreter-exceptions.bro, line 28: field value missing [p$ip]
+1300475167.096535 expression error in /Users/jsiwek/Projects/bro/bro/testing/btest/.tmp/core.dns-interpreter-exceptions/dns-interpreter-exceptions.bro, line 49: field value missing [p$ip]
+1300475168.902195 expression error in /Users/jsiwek/Projects/bro/bro/testing/btest/.tmp/core.dns-interpreter-exceptions/dns-interpreter-exceptions.bro, line 39: field value missing [p$ip]
+1300475168.902195 expression error in /Users/jsiwek/Projects/bro/bro/testing/btest/.tmp/core.dns-interpreter-exceptions/dns-interpreter-exceptions.bro, line 12: field value missing [p$ip]
+timeout g(), F
+timeout g(), T
+timeout
+g() done, no exception, T
+localhost resolved
+localhost resolved from f(), T
+localhost resolved from f(), F
+f() done, no exception, T
diff --git a/testing/btest/core/dns-interpreter-exceptions.bro b/testing/btest/core/dns-interpreter-exceptions.bro
new file mode 100644
index 0000000000..a795971b58
--- /dev/null
+++ b/testing/btest/core/dns-interpreter-exceptions.bro
@@ -0,0 +1,63 @@
+# @TEST-EXEC: bro -b -r $TRACES/wikipedia.trace %INPUT >out 2>&1
+# @TEST-EXEC: TEST_DIFF_CANONIFIER=$SCRIPTS/diff-remove-abspath btest-diff out
+# interpreter exceptions in "when" blocks shouldn't cause termination
+global p: pkt_hdr;
+
+function f(do_exception: bool): bool
+	{
+	return when ( local addrs = lookup_hostname("localhost") )
+		{
+		print "localhost resolved from f()", do_exception;
+		if ( do_exception )
+			print p$ip;
+		return T;
+		}
+	return F;
+	}
+
+function g(do_exception: bool): bool
+	{
+	return when ( local addrs = lookup_hostname("localhost") )
+		{
+		print "shouldn't get here, g()", do_exception;
+		}
+	timeout 0 sec
+		{
+		print "timeout g()", do_exception;
+		if ( do_exception )
+			print p$ip;
+		return T;
+		}
+	return F;
+	}
+
+event bro_init()
+	{
+	when ( local addrs = lookup_hostname("localhost") )
+		{
+		print "localhost resolved";
+		print p$ip;
+		}
+
+	when ( local addrs2 = lookup_hostname("localhost") )
+		{
+		print "shouldn't get here";
+		}
+	timeout 0 sec
+		{
+		print "timeout";
+		print p$ip;
+		}
+
+	when ( local b = f(T) )
+		print "f() exception done (shouldn't be printed)", b;
+
+	when ( local b2 = g(T) )
+		print "g() exception done (shouldn't be printed)", b2;
+
+	when ( local b3 = f(F) )
+		print "f() done, no exception", b3;
+
+	when ( local b4 = g(F) )
+		print "g() done, no exception", b4;
+	}