First of all, the syntax of this configuration file is far from being
perfect. If you’ve got some better ideas just drop me a line...
/etc/uif/uif.conf is the default configuration file for uif(8). This
file may contain several sections and comments. Each section begins with
the section name and the left curly brace and ends with the right curly
brace in a single line. A comment starts with a hash mark (#) at the
beginning of a line.
Blank lines are silently ignored. The following sections are valid:
include, sysconfig, service, network, interface, marker, filter, nat,
input, output, forward, masquerade and stateless.
The sections service, network, marker and interface have all a very
similar syntax. Each line starts with an identifier followed by one or
more blanks and one or more section specific entries or defined
identifiers separated by blanks. A valid identifier is case sensitive
and consists of letters, digits, underscores and hyphens.
If two or more identifiers in one section are equal, the corresponding
entries are merged to the first identifier. Hence, it’s not possible to
overwrite perviously defined identifiers. As a result the order of the
section entries is irrelevant and it’s possible to define a section more
Include other configuration files. Each line in this section, enclosed in
quotation marks ("), must be a valid filename. The contents of this file
are added to the actual configuration file and each file should contain
at least one section (a comment only file is not really useful...).
Set some global settings. Each line in this section starts with one of
the following identifiers followed by one or more blanks and the desired
value: LogLevel, LogPrefix, LogLimit, LogBurst, Limit, Burst and
AccountPrefix. If there are multiple definitions of one entry the last
definition is stored.
A valid default log priority (see syslog.conf(5))
The default log prefix. Each iptables logmessage starts with this
The default limit value for logmessages (see iptables(8))
The default burst value for logmessages (see iptables(8))
Limit The default limit value (see iptables(8))
Burst The default burst value (see iptables(8))
The default prefix for accounting chains.
This section defines all needed services. A service description starts
with the protocol (see protocols(5)) followed by parameters in
parenthesis. Most protocols don’t need any parameters. The only
exceptions are tcp, udp and icmp. The tcp and udp parameter defines the
source and destionation port(-range). The source and destination ports
are separated by a slash (/) and portranges are separated by a colon (eg.
tcp(123:333/99): tcp protocol, source-portrange 123-333, destination port
99). Empty source or destination ports are expanded to 1:65535. The icmp
protocol parameter must be a valid icmp type (see iptables -p icmp
This section defines all needed networks and hosts. A network description
starts with a valid IPv4 address (dotted quad), an optional netmask in
cidr notation (number of bits) or an optional MAC-address (with a
prefixed equal sign (=). Some valid entries are: 127.0.0.1 127.0.0.0/8
This section defines all needed (physical and bridged) interfaces (eg.
eth0, lo, ppp0).
This section defines all needed numerical (decimal) values for packet
filter, nat, input, output, forward, masquerade and stateless sections
Due to better partitioning of the packetfilter, rules can be split into
these sections. Internally they are equivalent and contain all rules. As
an exception to all other sections the order of entries in these sections
The default policy for the chains INPUT, OUTPUT and FORWARD is DROP (see
iptables(8)) and it’s not possible to change this.
Each line in in this section begins with in, out, fw, nat, masq, slin,
slout or slfw followed by ’+’, ’-’ or a mark identifier enclosed in curly
braces (or, in case of fw followed by ’>’). The identifiers in, out and
fw define rules for incoming, outgoing and forwarded IP-packets. Each
packet with an INVALID state (see iptables(8)) is matched by slin, slout
and slfw. The lines starting with nat and masq define rules to modify the
source or destination address or the destination port.
The plus and minus signs specify the type of the rule: ’+’ accepts
matching packets and ’-’ drops them. As a special case the identifier out
and fw accept the greater than (>) sign to modify the MSS depending on
the PMTU (see iptables(8))
A very basic ruleset may look like this: out+
This allows every outgoing traffic and rejects all incoming connections
(because of the default policy).
To be more specific, each line may contain several parameters. Each
parameter starts with a single character followed by an equal sign (=)
and one or more previously defined identifiers (in the corresponding
sections) separated by commas. The following parameters are valid:
s The source address or network.
d The destination address or network.
i The input interface.
o The output interface.
pi The physical input interface (only useful when used with bridged
po The physical output interface (only useful when used with bridged
p The service description (protocol).
m The mark field associated with a packet.
S The the new source address in nat rules.
D The the new destination address in nat rules.
P The the new service description in nat rules. This is only valid
with tcp or udp packets.
f This parameter sets some ’flags’. A flag definition starts with
the flag identifier and optional parameters in parenthesis. Valid
log - Logs matching packages to syslog. The given parameter is
included in the log entry. The number of logged packets and the
loglevel can be set in the sysconfig section.
reject - Only valid in DROP rules. This is used to send back an
error packet in response to the matched packet. The default
behaviour is a packet with set RST flag on tcp connections and a
destination-unreachable icmp packet in every other case. Valid
parameters are listed in iptables(8) in the REJECT section.
account - Create an accounting chain for all matching packages
and possible responses. The optional parameter is a part of the
name of the chain.
limit - Limits the number of matching packets. The default values
are set in the sysconfig section. Other values can be defined
with the optional parameter. The first entry sets a new limit
and the second parameter (separated by a comma (,)) sets the
burst value (see Limit and Burst in sysconfig section).
It’s possible to invert the identifier of one of following parameters -
if it expands to ecactly one object - by prepending a exclamation mark
(!): s, d, i, o, p (eg.: s=!local p=!http).
Configuration files are located in /etc/uif. There is a sample
configuration in /usr/share/doc/uif/uif.conf.tmpl.gz.
This manual page was written by Jörg Platte <firstname.lastname@example.org> and
Cajus Pollmeier <email@example.com>, for the Debian GNU/Linux system
(but may be used by others).