Network Traceroute

Map the exact routing path your packets take across the Internet to reach a destination server.

How Traceroute Works (TTL)

Traceroute works by intentionally manipulating the Time-To-Live (TTL) field in IP packets. TTL isn't actually a measure of time; it's a "hop limit."

1. The tool sends a packet with TTL=1. The very first router it hits decreases the TTL to 0, drops the packet, and sends back an "ICMP Time Exceeded" error. That error reveals router #1's IP address.

2. It then sends a packet with TTL=2. The first router decreases it to 1, passes it to router #2. Router #2 decreases it to 0, drops it, and replies. Now we know router #2.

This process repeats, incrementing the TTL until the packet finally hits the destination server. If you see * * * in the results, it means a specific router in the chain is configured to silently drop packets instead of replying, usually for security/DDoS protection.

Our Traceroute Tool maps the network path to any host, showing each router along the way and the round-trip time to reach it. Use it to locate where latency is introduced, identify which network a connection fails in, and understand how traffic actually reaches a destination.

What is Traceroute?

Traceroute discovers the sequence of routers between you and a destination by exploiting the TTL field in the IP header.

Each packet carries a time-to-live value that every router decrements. When it reaches zero the router discards the packet and returns an ICMP Time Exceeded message identifying itself. Traceroute sends packets with TTL set to 1, then 2, then 3 and so on, collecting a reply from each successive router until the destination is reached.

The result is a list of hops with round-trip times. It is genuinely useful, but it has real limitations: the reverse path may differ from the forward path, many routers deprioritise or block the ICMP replies traceroute depends on, and the timing shown reflects the round trip to that router rather than the latency of the path segment.

Maps the routers between you and a destination
Works by incrementing the TTL field and collecting ICMP replies
Shows round-trip time to each hop, not per-segment latency
The return path may differ from the outbound path
Many routers rate limit or block the replies it relies on

Why Traceroute Matters

When a connection is slow or failing, traceroute tells you where. A path that runs cleanly for eight hops and then times out identifies which network the problem is in, which determines who you should be talking to — your ISP, a transit provider, or the destination operator.

It also reveals routing that is genuinely surprising. Traffic between two hosts in the same city can transit another continent depending on peering arrangements, and that kind of path explains latency that is otherwise inexplicable.

Identifies which network a connection problem occurs in
Shows where latency is actually introduced along a path
Reveals unexpected routing through distant regions
Provides evidence when reporting a problem to a provider
Helps distinguish a local issue from a destination issue

How This Traceroute Tool Works

The tool sends probes with increasing TTL values and records each responding router.

Validates the host input against format and SSRF safety checks
Resolves the hostname to an address if needed
Sends probes with TTL values incrementing from one
Records the responding router and round-trip time at each hop
Continues until the destination replies or the hop limit is reached

How to Use the Traceroute Tool

Enter a hostname or IP address in the input field
Run the trace to map the network path
Read the hops in order from your side to the destination
Look for where round-trip times increase sharply
Note where the trace stops, if it does not reach the destination

Understanding Your Traceroute Results

Each line is one hop. Here is how to read them:

Field / Value	Meaning
`Hop number`	Position in the path, starting at your nearest router. Early hops are your local network and ISP; middle hops are transit; final hops are the destination network.
`Round-trip time`	Time for a probe to reach that router and for its reply to return. It is cumulative from your position, not the latency of that single segment.
`Hostname`	The reverse DNS name of the router, where one exists. Operator naming conventions often encode the city and role, which helps identify the path geography.
`Asterisks`	No reply from that hop. Usually the router is configured not to respond or is rate limiting ICMP, not that traffic stopped there. Traffic passing through is normal.
`Latency jump`	A sharp increase between consecutive hops. Often a long-distance link such as a submarine cable, which is expected, or genuine congestion, which is not.
`Trace stops`	No replies from a hop onwards to the destination. May mean a firewall silently dropping probes, which is common, or a genuine break in the path.
`Repeated hop`	The same router appearing multiple times indicates a routing loop, which is a real fault and will prevent traffic reaching the destination.

Common Problems & How to Fix Them

This usually means a firewall is silently dropping the probes rather than that the path is broken.

Confirm by testing the actual service — if you can open a TCP connection to the destination port, the path works and the trace result is simply an artefact of ICMP filtering. Many hosts and cloud providers block ICMP by default.

Those routers are configured not to reply to expired packets, or are rate limiting ICMP under load. This is extremely common and is not a fault.

As long as later hops respond, traffic is passing through normally. Only a complete absence of replies from one hop onwards, combined with an actual connectivity failure, indicates a real problem.

Determine whether it is geography or congestion. A jump of 70 to 150 milliseconds usually indicates an intercontinental link, which is physics rather than a fault — check the hop hostnames for city codes.

A large jump between two routers in the same region, particularly one that varies between runs, suggests congestion. That is worth raising with whichever operator runs that segment.

A routing loop. Packets are circulating between routers and will never reach the destination, expiring when their TTL runs out.

This is a genuine fault in the network where the loop occurs, usually caused by a routing misconfiguration. Report it to the operator of those hops, supplying the traceroute output as evidence.

Routing follows peering and transit relationships rather than geography, so traffic between nearby points can cross a continent.

There is usually nothing you can do directly. If the latency matters, a CDN or a provider with better regional peering is the practical remedy rather than trying to influence routing.

Best Practices

Run several traces, since a single run can be misleading under transient load
Read hop hostnames for city codes that reveal the path geography
Treat asterisks as normal unless they coincide with an actual failure
Compare against a trace to a known-good destination for context
Remember round-trip times are cumulative, not per-segment
Include traceroute output when reporting problems to a provider
Confirm apparent failures by testing the actual service port

Security Recommendations

Be aware traceroute reveals your network topology to anyone tracing towards you
Consider rate limiting ICMP replies on your own infrastructure to limit reconnaissance value
Avoid router hostnames that disclose internal roles or equipment models
Remember attackers use traceroute to map perimeter devices and identify the upstream provider
Do not rely on blocking ICMP as a security measure, since it only slightly inconveniences mapping
Treat an unexpected change in the path to your own infrastructure as a possible routing hijack

Frequently Asked Questions

The sequence of routers between you and a destination, with the round-trip time to each. It works by sending packets with increasing TTL values and collecting the ICMP Time Exceeded replies that routers return.

Those routers are configured not to reply to expired packets, or are rate limiting ICMP. This is very common and does not mean traffic stopped there — as long as later hops respond, packets are passing through normally.

Usually a firewall at or near the destination is dropping the probes. Test whether the actual service responds — if a TCP connection succeeds, the path is fine and the trace result is just an artefact of ICMP filtering.

Cumulative. Each figure is the time for a probe to reach that router and for its reply to return to you. To estimate a single segment, compare consecutive hops — though asymmetric return paths make this approximate.

Routers deprioritise generating ICMP replies relative to forwarding traffic, so a busy router can appear slow while forwarding perfectly. A single elevated hop followed by normal ones is not a problem.

A routing loop. Packets circulate between routers until their TTL expires and never reach the destination. It is a genuine fault caused by routing misconfiguration and should be reported to the operator of those hops.

Often not. Internet routing is frequently asymmetric, so replies may take a completely different route. This is why traceroute shows you only one direction and why a trace from the other end can look quite different.