ping vs traceroute vs mtr

ping — end-to-end liveness

ping sends ICMP echo requests to a host. It answers “is there IP reachability and what is RTT variance?” It does not show which hop dropped packets, and many routers rate-limit ICMP while still forwarding TCP.

traceroute — hop discovery

Classic traceroute raises TTL to force each hop to return ICMP time-exceeded or TCP RST/UDP ICMP errors depending on mode. Use it to see asymmetric paths or unexpected detours, not fine-grained loss percentages.

mtr — rolling sample

mtr continuously probes each hop like ping plus traceroute, producing loss% and average RTT per hop. Run long enough to smooth spikes; interpret middle-hop “100% loss” artifacts cautiously.

Tool	Best for	Blind spot
ping	Quick up/down, jitter	No per-hop blame
traceroute	Initial path map	Single snapshot
mtr	Trended loss/latency	ICMP deprioritization

Frequently Asked Questions

Q.When should I trust mtr over traceroute?

When diagnosing intermittent loss—mtr aggregates hundreds of probes; traceroute is a single pass that may miss bursty congestion.

Q.Why does mtr show loss on a middle hop but not the destination?

Routers may discard low-priority ICMP while still forwarding transit traffic—focus on sustained loss to the last responsive hop and validate with TCP.

Q.Does ping prove my HTTPS app works?

No—middleboxes treat ICMP differently. Pair ICMP tools with curl, openssl s_client, or application-level probes.

Q.Which traceroute mode should I use behind firewalls?

Try TCP or UDP traceroute variants when ICMP is blocked; each reveals different ACL behavior.

Q.Why must mtr sometimes run as root?

Certain raw-socket modes or timing features require privileges—use TCP mode or distro builds that support unprivileged operation when possible.

Q.How long should I run mtr before opening an ISP ticket?

Several minutes minimum, ideally through a suspected failure window, and include upload saturation notes if bufferbloat is possible.

Q.Is IPv6 diagnosis different?

Yes—use `ping -6`, `traceroute6`/`mtr -6`, and verify local ULA vs global scope; separate RAs can change default paths.

Q.What should I paste into a support ticket?

Text `mtr --report` output, source/dest IPs, timestamps, and whether the issue reproduces on wired vs Wi-Fi—avoid screenshots only.