tunping

If ping shows something like 0.01 ms with ttl=64 after you enable the VPN, the ping is intercepted and answered locally. ICMP lies. tunping measures the real latency instead. With --compare it runs the same probe via two interfaces (VPN and direct), so the VPN overhead shows up as one number.

This is NOT ICMP. tunping times an HTTPS round-trip (HEAD / → first response byte) over one persistent connection.

Background

• SOCKS-TUN mode (tun2socks/XRay-style): ping and hping -S / mtr --tcp are all answered by the local TUN device, so they report garbage, typically under 1 ms.
• tunping works in that case because it times payload, not handshake.

What it looks like

With the VPN on, ping outputs:

$ ping 1.1.1.1
64 bytes from 1.1.1.1: icmp_seq=1 ttl=64 time=0.01 ms

$ ping 192.0.2.1    # TEST-NET answers (it should never)
64 bytes from 192.0.2.1: icmp_seq=1 ttl=64 time=0.01 ms

$ traceroute -n 1.1.1.1
 1  * * *
 2  * * *

The true round-trip is slower:

$ tunping 1.1.1.1 -c 1
response from 1.1.1.1 (1.1.1.1): seq=1 ttfb=100.0 ms

Install

All distros (pipx):

pipx install tunping

Without pipx/uv:

python3 -m venv tunping-venv
source tunping-venv/bin/activate
pip install tunping

Arch Linux:

git clone https://github.com/mceblvn/tunping.git
cd tunping/packaging/aur
makepkg -si

Python >= 3.10, stdlib only, no deps.

Use

tunping 1.1.1.1 -c 4
tunping 1.1.1.1 -c 4 --json
tunping example.com -c 10 -i 0.5 --port 443 --timeout 5
tunping 1.1.1.1 --proto http --port 80 -c 2
tunping 1.1.1.1 --sni cloudflare-dns.com --insecure -c 2  # SNI override
tunping 1.1.1.1 -c 4 --compare tun2 enp14s0

--compare probes both interfaces and shows the delta

Output mimics ping by default:

TUNPING 1.1.1.1 (1.1.1.1:443) with HTTPS TTFB
response from 1.1.1.1 (1.1.1.1): seq=1 ttfb=182.4 ms
...
--- 1.1.1.1 tunping statistics ---
4 transmitted, 4 received, 0.0% loss
rtt min/avg/max/mdev = 181.2/183.1/185.4/1.5 ms
jitter = 2.1 ms

JSON (--json): one object per probe {"type":"probe",...} plus final {"type":"summary",...} is handy for graphs/scripts.

Exit codes: 0 if any probe succeeded, 1 if all lost, 2 on usage error.

License

MIT.