ip-rule: add page (#6504)

pages/linux/ip-rule.md

@@ -0,0 +1,36 @@
+# ip rule
+
+> IP routing policy database management.
+> More information: <https://man7.org/linux/man-pages/man8/ip-rule.8.html>.
+
+- Display the routing policy:
+
+`ip rule {{show|list}}`
+
+- Add a new rule based on packet source addresses:
+
+`sudo ip rule add from {{192.168.178.2/32}}`
+
+- Add a new rule based on packet destination addresses:
+
+`sudo ip rule add to {{192.168.178.2/32}}`
+
+- Delete a rule based on packet source addresses:
+
+`sudo ip rule delete from {{192.168.178.2/32}}`
+
+- Delete a rule based on packet destination addresses:
+
+`sudo ip rule delete to {{192.168.178.2/32}}`
+
+- Flush all deleted rules:
+
+`ip rule flush`
+
+- Save all rules to a file:
+
+`ip rule save > {{path/to/ip_rules.dat}}`
+
+- Restore all rules from a file:
+
+`ip rule restore < {{path/to/ip_rules.dat}}`