Show the running kernel
Read-onlyuname -rExpect: On XanMod the string usually contains xanmod.
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03 / FIELD NOTES
BBRv3 still reports bbr
Inspect kernel and congestion control; the name bbr alone does not identify its version.
Why this way
The congestion control name does not encode a version. XanMod currently documents BBRv3, but the running kernel and its exact release determine what your server uses.
When to use
The XanMod kernel is installed and you want to see which congestion control is active.
When not to
Do not infer a BBR version from the sysctl string alone. Check the running kernel release and its changelog.
Prerequisites
- Linux host with sysctl
Steps
Show TCP congestion control
Read-onlysysctl net.ipv4.tcp_congestion_controlExpect: The value is still bbr on XanMod; that kernel implements BBRv3.
What it changes
Read-only. Compare the running kernel and its upstream release notes.
Related
Sources
{
"slug": "bbr-name",
"risk": "safe",
"tags": [
"bbr",
"xanmod",
"sysctl"
],
"updated": "2026-10-30",
"pathIndex": null,
"why": "The congestion control name does not encode a version. XanMod currently documents BBRv3, but the running kernel and its exact release determine what your server uses.",
"steps": [
{
"command": "uname -r",
"risk": "safe"
},
{
"command": "sysctl net.ipv4.tcp_congestion_control",
"risk": "safe"
}
]
}