NAME
pflog — packet filter logging interface
SYNOPSIS
device pflog
DESCRIPTION
The pflog interface is a device which makes visible all packets logged by the packet filter, pf(4). Logged packets can easily be monitored in real time by invoking tcpdump(1) on the pflog interface, or stored to disk using pflogd(8).
The pflog0 interface is created automatically at boot if both pf(4) and pflogd(8) are enabled; further instances can be created using ifconfig(8).
Each packet retrieved on this interface has a header associated with it of length PFLOG_HDRLEN. This header documents the address family, interface name, rule number, reason, action, and direction of the packet that was logged. This structure, defined in ⟨ net/if_pflog.h⟩ looks like
struct pfloghdr {
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u_int8_t |
length; |
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sa_family_t |
af; |
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u_int8_t |
action; |
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u_int8_t |
reason; |
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char |
ifname[IFNAMSIZ]; |
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char |
ruleset[PF_RULESET_NAME_SIZE]; |
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u_int32_t |
rulenr; |
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u_int32_t |
subrulenr; |
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uid_t |
uid; |
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pid_t |
pid; |
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uid_t |
rule_uid; |
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pid_t |
rule_pid; |
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u_int8_t |
dir; |
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u_int8_t |
pad[3]; |
};
EXAMPLES
Create a pflog interface and monitor all packets logged on it:
# ifconfig
pflog1 up
# tcpdump -n -e -ttt -i pflog1
SEE ALSO
tcpdump(1), inet(4), inet6(4), netintro(4), pf(4), ifconfig(8), pflogd(8)
HISTORY
The pflog device first appeared in OpenBSD 3.0.
BSD May 31, 2007 BSD