2 entries
iptables & UFW
Linux firewall log lines, and how to read the key-value format.
- IN= OUT= iptables: a packet was logged by a firewall rule Informational The Linux kernel firewall matched a packet against a rule with logging enabled and wrote the packet header to the kernel log. The format is dense and unpunctuated, but every field is a key-value pair and it reads easily once you know the order.
- UFW BLOCK UFW BLOCK: Ubuntu's firewall dropped a packet Informational UFW blocked a connection. It is the same netfilter logging underneath as raw iptables, just with a recognisable prefix — and on any machine reachable from the internet, the volume is normal and expected.