GITBOOK-425: change request with no subject merged in GitBook

Author: defguard-community

SUMMARY.md

@@ -144,3 +144,4 @@
   * [Client "All traffic" connection issues](resources/troubleshooting/client-all-traffic-connection-issues.md)
   * [WebAuthn security keys](resources/troubleshooting/webauthn-security-keys.md)
   * [Unable to sign in to your defguard instance with correct credentials](resources/troubleshooting/unable-to-sign-in-to-your-defguard-instance-with-correct-credentials.md)
+  * ["No buffer space available" error in the gateway logs](resources/troubleshooting/no-buffer-space-available-error-in-the-gateway-logs.md)

resources/troubleshooting/no-buffer-space-available-error-in-the-gateway-logs.md

@@ -0,0 +1,50 @@
+# "No buffer space available" error in the gateway logs
+
+## Problem
+
+The following error appears in the gateway logs:
+
+```bash
+Interface configuration failed: Firewall error: Netlink error: Failed while reading a message from socket: Os { code: 105, kind: Uncategorized, message: "No buffer space available" }
+```
+
+## Symptoms
+
+* This error appears in the logs.
+* VPN functionality continues to work.
+* No stats are visible on the dashboard.
+
+## Cause
+
+This issue is related to **insufficient socket buffer sizes** on the host system, which causes the Netlink communication with the Linux kernel to fail.
+
+## Solution
+
+To resolve the issue, increase the system's socket buffer sizes by updating your `sysctl.conf` file.
+
+#### 1. Edit `/etc/sysctl.conf`
+
+Add the following lines to the end of your file:
+
+```bash
+bashCopyEdit# Increase socket buffer sizes
+net.core.rmem_max = 67108864
+net.core.wmem_max = 67108864
+net.ipv4.tcp_rmem = 4096 87380 67108864
+net.ipv4.tcp_wmem = 4096 65536 67108864
+net.core.rmem_default = 524288
+net.core.wmem_default = 524288
+```
+
+#### 2. Apply the changes
+
+Run the following command to reload the settings:
+
+```bash
+sudo sysctl -p
+```
+
+## Verification
+
+* Check the gateway logs to ensure the error no longer appears.
+* Confirm that stats are now visible in the dashboard.