Visual Route Tracer & Map
Trace packet journeys across the global Internet backbone. Inspect every intermediate router hop, analyze BGP transit providers, and visualize the physical route on an interactive OpenStreetMap.
Understanding Traceroute Hops & Why Asterisks (* * *) Appear on Intermediate Routers
When analyzing a traceroute output, users often notice one or two hops showing * * * Request timed out while subsequent hops reply normally with low latency. This is frequently mistaken for packet loss or a network outage, but in 99% of cases, it is intentional router control plane rate-limiting.
Traceroute sends packets starting with Time-To-Live (TTL) = 1. Each intermediate router decrements TTL by 1. When TTL hits 0, the router discards the packet and generates an ICMP Type 11 Code 0 (Time Exceeded) error back to the sender.
Generating ICMP Time Exceeded packets requires the router's main CPU (Control Plane). Backbone routers hardware-forward normal traffic at 400 Gbps (Data Plane) but strictly rate-limit or discard CPU-intensive ICMP error generation to prevent DoS attacks.
Internet traffic is almost always asymmetric: the path your outbound packets take through Tier-1 carriers (e.g. Lumen, Telia) differs from the return path chosen by destination autonomous systems via BGP hot-potato routing.
Traceroute Protocols: ICMP vs. UDP vs. TCP SYN Probing
How different operating systems execute route tracing and navigate firewall filters.
| Protocol | Default OS | How It Triggers Response | Firewall & NAT Traversal |
|---|---|---|---|
ICMP Echo (tracert) | Microsoft Windows | Sends ICMP Echo Requests (Type 8); waits for ICMP Echo Reply (Type 0) at target. | Often blocked at enterprise borders and perimeter firewalls. |
UDP Probing (traceroute) | Linux, macOS, BSD | Sends high-port UDP datagrams (33434–33534); destination replies with ICMP Port Unreachable. | Standard default; high-port UDP occasionally filtered by ISP egress rules. |
TCP SYN (tcptraceroute) | Specialized DevOps / Security | Sends TCP SYN packets to port 80/443; destination replies with SYN-ACK or RST. | Best firewall traversal; mimics standard HTTPS web browser traffic. |
Recommended Complementary Network Tools
Correlate traceroute path latency with local jitter tests, public IP geolocation, and firewall rules:
My IP & Geolocation Map
Inspect your public WAN IP, WebRTC local LAN interface, and ISP PoP on OpenStreetMap.
Network Jitter & Ping Test
Calculate RFC 3550 statistical jitter, bufferbloat, and packet variance with live oscilloscope graphs.
Inbound Port Checker
Verify whether ports 22, 80, 443, and 3389 are reachable on your destination host.