{
  "id": 1871904,
  "title": "Your sysctl says one thing, the kernel says another",
  "url": "https://urgent.news/2026/08/19/your-sysctl-says-one-thing-the-kernel-says-another",
  "topic": "tech",
  "section": "Tech",
  "published": "2026-08-19T05:06:12.000Z",
  "source": {
    "name": "Dev.to",
    "slug": "dev-to",
    "url": "https://dev.to/ricco020/your-sysctl-says-one-thing-the-kernel-says-another-4gha"
  },
  "original_language": "en",
  "account": "A sysctl configuration may appear correct in a file, but the kernel may be applying a different value. This discrepancy can lead to issues like a WireGuard tunnel with no traffic. The primary reason for this behavior is the presence of a second sysctl file managed by UFW, which takes precedence over the original /etc/sysctl.conf file. When UFW is enabled, any settings made in /etc/sysctl.conf are overwritten silently, without any warning or log entry. This can be a time-consuming issue as users may repeatedly check the same file they edited, believing it to be correct.\n\nTo check the effective sysctl values, users should look in /proc/sys/net/ipv4/ip_forward instead of relying solely on the file /etc/sysctl.conf. The notation may use slashes in the latter, which can cause confusion when searching for the correct configuration. A helpful script has been created to compare effective sysctl values against hardening recommendations and flag any discrepancies, making it easier for users to identify and resolve the issue.",
  "summary": "You set net.ipv4.ip_forward=1 in /etc/sysctl.conf . You rebooted. The value is still 0 . Nothing is broken, and you did not make a typo. On a host running UFW, there is a second sysctl file, and it wins . Two files, one kernel UFW ships /etc/ufw/sysctl.conf and loads it when the firewall comes up. It takes precedence over /etc/sysctl.conf . Anything you set in the familiar file that UFW also sets…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}