pf (Packet Filter) is the TCP/IP packet filtering firewall subsystem on BSD systems.

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NAT and source IP filtering in PF, using OpenBSD >= 4.7

I just read a book about PF (The Book Of PF, No Starch), but there's one question not answered by it. If I have a gateway machine using two interfaces, $int_if and $ext_if, and I NAT the packages ...
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PF's keep state on UDP packets = security issue?

During the last few days I've read a lot about PF as a nice alternative to iptables and a much more improved and secure way of filtering. Nevertheless I came across the following statement which I ...
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“persist” attribute in OpenBSD Tables

According to OpenBSD's FAQs on "Tables" (http://www.openbsd.org/faq/pf/tables.html), without the persist attribute, the kernel will automatically remove the table when the last rule referencing ...
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How to only allow a group for network access?

Using OpenBSD's pf. Question: How can we modify the firewall of OpenBSD to allow ONLY a given group for network access? If somebody isn't in that group, it shouldn't have layer 3 or layer 2 network ...
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TLS and Packet Filtering

I want to set up a client wit BSD packet filtering that only allows outgoing 443 connections. Would this do the trick in my pf.conf? block out block in pass out on eth0 inet proto tcp from (eth0) ...
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pf out interface?

I'm trying to figure out how to allow all hosts in $dmz to reach any host when egressing $extif. I can't seem to find the equivalence of netfilters "-o $extif", and I'd like to avoid specifically ...
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FreeBSD pf firewall, new connections severly delayed when nating

I have a newly setup fbsd 9.1 with pf, which itself doesn't experience any slowness when for example downloading a debian iso from my local debian repo (ftp.se.debian.org). Any machine behind it, ...
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Can not divert packet to pf when configure transparent squid 3.4.13 on OpenBSD 5.7

I am trying to build transparent proxy with squid on OpenBSD 5.7 with pf firewall. I compile squid from sources with options: $ squid -v Squid Cache: Version **3.4.13** configure options: ...
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Why isn't my nat-to not applied to the pass out rule?

I've a strange problem concerning NAT on an OpenBSD-Box with pf. I've cut down my pf.conf to the following lines: extif = "pcn0" intif = "pcn1" block drop all #Allow all incoming traffic from intif ...
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I have a firewall bridge in pfSense and I want to log only the allowed packet

I have a bridge0 which has members em0 (wan) and vge0 (lan) I connect via ssh on vge0, when I tcpdump -i pflog0 I get the blocked packets from the bridge0, but when I tcpdump -i bridge0 I get both ...
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Perform Cisco's DNS Doctoring on FreeBSD

How to perform a change in the DNS response from a DNS server to be a different IP address than the DNS server actually answered for a given name? ...
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Configure FreeBSD pf firewall (non GUI) for beginner

I am running Mac OS X 10.10, but my research has led me to the understanding that the particular flavor of pf was ported from FreeBSD. I have tried the popular GUI software (IceFloor) but it is a bit ...
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pf.conf syntax error

I copied this pf.conf from a website rdr-anchor "forwarding" load anchor "forwarding" from "/Users/jeff/Documents/pf.rules" and this pf.rules rdr-anchor "forwarding" load anchor "forwarding" from ...