$devvkit learn --librarie mtr-guide

MTR Guide

[networking][traceroute][latency][cli]

Network Diagnostics

Install

sudo apt install mtr
brew install mtr
# Windows: WinMTR (GUI) or WSL
# macOS: brew install mtr

MTR (My TraceRoute) continuously probes each hop along a network path and reports packet loss and latency statistics per hop. Unlike a single traceroute, MTR runs for many cycles and aggregates stats, making transient packet loss visible.

Use `-r` for report mode (single shot with 10 cycles by default), `-c` to control cycle count, `-n` to skip DNS resolution, `-i` for interval between probes. The default protocol is ICMP; use `-T` for TCP and `-u` for UDP probes.

Packet loss at the first hop usually means your local network/modem issue. Loss only at later hops often means those intermediate routers are rate-limiting ICMP. Loss at the final hop that persists with TCP mode indicates actual network problems.

Basic

Continuous view— Live TUI display.

mtr example.com
mtr 8.8.8.8
mtr -n 8.8.8.8              # No DNS (faster)
mtr -4 8.8.8.8               # Force IPv4
mtr -6 google.com            # Force IPv6

Report Mode

Report mode— Single-shot output.

mtr -r 8.8.8.8                         # 10 cycles, then print & exit
mtr -r -c 100 8.8.8.8                   # 100 cycles
mtr -r -c 100 -n 8.8.8.8                # No DNS, 100 cycles
mtr -r -c 300 -i 0.5 8.8.8.8            # 300 cycles, 0.5s interval

CSV output— Machine-readable.

mtr -r -c 50 -n --csv 8.8.8.8 > mtr.csv
# Columns: host, loss%, sent, last, avg, best, worst, stddev
mtr -r -c 50 -n --json 8.8.8.8 | jq '.report.hubs[] | {host, loss: .Loss, avg: .Avg}'
mtr -r -c 50 -n --xml 8.8.8.8 > mtr.xml

Protocol Selection

TCP mode— Use TCP SYN instead of ICMP.

sudo mtr -T example.com -P 443        # TCP to port 443
sudo mtr -T -n 1.1.1.1 -P 853         # TCP to DNS-over-TLS port
# TCP mode bypasses ICMP rate-limiting on many routers

UDP mode— UDP probes.

sudo mtr -u example.com -P 53         # UDP to DNS port
sudo mtr -u -n 8.8.8.8 -P 443
# Some networks treat UDP differently from ICMP/TCP

Advanced

Bandwidth test— Use MTR bandwidth mode.

sudo mtr --report-wide example.com      # Wide columns
sudo mtr --show-ips 8.8.8.8            # Show IPs per hop
sudo mtr --order "L SR DR" 8.8.8.8    # Custom column order

Compare paths— Check multiple routes.

# Run two MTRs simultaneously to compare paths:
mtr -r -n -c 30 1.1.1.1 > cloudflare.log &
mtr -r -n -c 30 8.8.8.8 > google.log &
wait
diff cloudflare.log google.log

# Also useful: check if traffic takes expected route
mtr -r -n -c 10 vpn-gateway.company.com

Trick: detect throttling— Spot traffic shaping.

mtr -r -c 100 -n --report-wide your-server.com
# Look for: sudden packet loss at one hop but not later hops
# = that hop is rate-limiting ICMP, not actual packet loss

# Confirm with TCP mode:
mtr -T -r -c 100 -n your-server.com
# If TCP shows no loss → it's just ICMP shaping