correctly reverse-resolve source of inbound connections

There were two problems:
- the renderer was looking for reverse names on the destination
- the probe was not annotating source nodes with reverse-resolved names

Fixes #1847

probe/endpoint/reporter.go

@@ -196,6 +196,9 @@ func (r *Reporter) addConnection(rpt *report.Report, t fourTuple, namespaceID st
 
 	// In case we have a reverse resolution for the IP, we can use it for
 	// the name...
+	if fromNames, err := r.reverseResolver.get(t.fromAddr); err == nil {
+		fromNode = fromNode.WithSet(ReverseDNSNames, report.MakeStringSet(fromNames...))
+	}
 	if toNames, err := r.reverseResolver.get(t.toAddr); err == nil {
 		toNode = toNode.WithSet(ReverseDNSNames, report.MakeStringSet(toNames...))
 	}

render/detailed/connections.go

@@ -145,7 +145,7 @@ func outgoingConnectionsSummary(topologyID string, r report.Report, n report.Nod
 				if !ok {
 					continue
 				}
-				key := newConnection(n, node, port, remoteEndpointID, localAddr)
+				key := newConnection(n, node, port, localEndpoint.ID, localAddr)
 				counts[key] = counts[key] + 1
 			}
 		}