diff --git a/src/Net.cc b/src/Net.cc
index 856fc75ae0..61deab227c 100644
--- a/src/Net.cc
+++ b/src/Net.cc
@@ -42,11 +42,11 @@ extern "C" {
 extern int select(int, fd_set *, fd_set *, fd_set *, struct timeval *);
 }
 
-iosource::PktDumper* pkt_dumper = 0;
+iosource::PktDumper* pkt_dumper = nullptr;
 
-int reading_live = 0;
-int reading_traces = 0;
-int have_pending_timers = 0;
+bool reading_live = false;
+bool reading_traces = false;
+bool have_pending_timers = false;
 double pseudo_realtime = 0.0;
 double network_time = 0.0;	// time according to last packet timestamp
 				// (or current time)
@@ -57,11 +57,11 @@ double last_watchdog_proc_time = 0.0;	// value of above during last watchdog
 bool terminating = false;	// whether we're done reading and finishing up
 bool is_parsing = false;
 
-const Packet *current_pkt = 0;
+const Packet *current_pkt = nullptr;
 int current_dispatched = 0;
 double current_timestamp = 0.0;
-iosource::PktSrc* current_pktsrc = 0;
-iosource::IOSource* current_iosrc = 0;
+iosource::PktSrc* current_pktsrc = nullptr;
+iosource::IOSource* current_iosrc = nullptr;
 
 std::list<ScannedFile> files_scanned;
 std::vector<string> sig_files;
@@ -153,7 +153,7 @@ void net_init(const std::string& interface,
 	if ( ! pcap_input_file.empty() )
 		{
 		reading_live = pseudo_realtime > 0.0;
-		reading_traces = 1;
+		reading_traces = true;
 
 		iosource::PktSrc* ps = iosource_mgr->OpenPktSrc(pcap_input_file, false);
 		assert(ps);
@@ -164,8 +164,8 @@ void net_init(const std::string& interface,
 		}
 	else if ( ! interface.empty() )
 		{
-		reading_live = 1;
-		reading_traces = 0;
+		reading_live = true;
+		reading_traces = false;
 
 		iosource::PktSrc* ps = iosource_mgr->OpenPktSrc(interface, true);
 		assert(ps);
@@ -176,11 +176,11 @@ void net_init(const std::string& interface,
 		}
 
 	else
-		// have_pending_timers = 1, possibly.  We don't set
+		// have_pending_timers = true, possibly.  We don't set
 		// that here, though, because at this point we don't know
 		// whether the user's zeek_init() event will indeed set
 		// a timer.
-		reading_traces = reading_live = 0;
+		reading_traces = reading_live = false;
 
 	if ( pcap_output_file )
 		{
@@ -192,11 +192,10 @@ void net_init(const std::string& interface,
 			reporter->FatalError("problem opening dump file %s (%s)",
 					     writefile, pkt_dumper->ErrorMsg());
 
-		ID* id = global_scope()->Lookup("trace_output_file");
-		if ( ! id )
-			reporter->Error("trace_output_file not defined in bro.init");
-		else
+		if ( ID* id = global_scope()->Lookup("trace_output_file") )
 			id->SetVal(new StringVal(writefile));
+		else
+			reporter->Error("trace_output_file not defined in bro.init");
 		}
 
 	init_ip_addr_anonymizers();
@@ -239,7 +238,7 @@ void net_packet_dispatch(double t, const Packet* pkt, iosource::PktSrc* src_ps)
 
 	expire_timers(src_ps);
 
-	SegmentProfiler* sp = 0;
+	SegmentProfiler* sp = nullptr;
 
 	if ( load_sample )
 		{
@@ -266,13 +265,13 @@ void net_packet_dispatch(double t, const Packet* pkt, iosource::PktSrc* src_ps)
 		{
 		delete sp;
 		delete sample_logger;
-		sample_logger = 0;
+		sample_logger = nullptr;
 		}
 
 	processing_start_time = 0.0;	// = "we're not processing now"
 	current_dispatched = 0;
-	current_iosrc = 0;
-	current_pktsrc = 0;
+	current_iosrc = nullptr;
+	current_pktsrc = nullptr;
 	}
 
 void net_run()
@@ -299,20 +298,20 @@ void net_run()
 				loop_counter = 0;
 			}
 #endif
-		current_iosrc = src;
+		current_iosrc = nullptr;
 		auto communication_enabled = broker_mgr->Active();
 
 		if ( src )
 			src->Process();	// which will call net_packet_dispatch()
 
 		else if ( reading_live && ! pseudo_realtime)
-			{ // live but  no source is currently active
-			double ct = current_time();
+			{
+			// live but no source is currently active
 			if ( ! net_is_processing_suspended() )
 				{
 				// Take advantage of the lull to get up to
 				// date on timers and events.
-				net_update_time(ct);
+				net_update_time(current_time());
 				expire_timers();
 				usleep(1); // Just yield.
 				}
@@ -353,7 +352,7 @@ void net_run()
 
 		processing_start_time = 0.0;	// = "we're not processing now"
 		current_dispatched = 0;
-		current_iosrc = 0;
+		current_iosrc = nullptr;
 
 		if ( signal_val == SIGTERM || signal_val == SIGINT )
 			// We received a signal while processing the
@@ -376,7 +375,7 @@ void net_run()
 
 			if (  ! have_active_packet_source )
 				// Can turn off pseudo realtime now
-				pseudo_realtime = 0;
+				pseudo_realtime = 0.0;
 			}
 		}
 
diff --git a/src/Net.h b/src/Net.h
index 54885fe45f..b1a3de427c 100644
--- a/src/Net.h
+++ b/src/Net.h
@@ -43,19 +43,19 @@ inline bool net_is_processing_suspended()
 	{ return _processing_suspended > 0; }
 
 // Whether we're reading live traffic.
-extern int reading_live;
+extern bool reading_live;
 
 // Same but for reading from traces instead.  We have two separate
 // variables because it's possible that neither is true, and we're
 // instead just running timers (per the variable after this one).
-extern int reading_traces;
+extern bool reading_traces;
 
 // True if we have timers scheduled for the future on which we need
 // to wait.  "Need to wait" here means that we're running live (though
 // perhaps not reading_live, but just running in real-time) as opposed
 // to reading a trace (in which case we don't want to wait in real-time
 // on future timers).
-extern int have_pending_timers;
+extern bool have_pending_timers;
 
 // If > 0, we are reading from traces but trying to mimic real-time behavior.
 // (In this case, both reading_traces and reading_live are true.)  The value