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This commit is contained in:
Jan Engelhardt
2013-06-02 16:53:56 +02:00
parent fe7a30c746
commit e027089782
23 changed files with 48 additions and 27 deletions
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1
extensions/libxt_CHAOS.man
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@@ -1,3 +1,4 @@
.PP
Causes confusion on the other end by doing odd things with incoming packets.
CHAOS will randomly reply (or not) with one of its configurable subtargets:
.TP

1
extensions/libxt_DELUDE.man
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@@ -1,3 +1,4 @@
.PP
The DELUDE target will reply to a SYN packet with SYN-ACK, and to all other
packets with an RST. This will terminate the connection much like REJECT, but
network scanners doing TCP half-open discovery can be spoofed to make them

1
extensions/libxt_DHCPMAC.man
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@@ -1,3 +1,4 @@
.PP
In conjunction with ebtables, DHCPMAC can be used to completely change all MAC
addresses from and to a VMware-based virtual machine. This is needed because
VMware does not allow to set a non-VMware MAC address before an operating

51
extensions/libxt_DNETMAP.man
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@@ -1,16 +1,16 @@
.PP
The \fBDNETMAP\fR target allows dynamic two-way 1:1 mapping of IPv4 subnets.
Single rule can map private subnet to shorter public subnet creating and
maintaining unambigeous private-public ip bindings. Second rule can be used to
map new flows to private subnet according to maintained bindings. Target allows
efficient public IPv4 space usage and unambigeous NAT at the same time.
.PP
Target can be used only in \fBnat\fR table in \fBPOSTROUTING\fR or \fBOUTPUT\fR
chains for SNAT and in \fBPREROUTING\fR for DNAT. Only flows directed to bound
IPs will be DNATed. Packet continues chain traversal if there is no free
postnat-ip to be assigned to prenat-ip. Default binding \fBttl\fR is \fI10
minutes\fR and can be changed using \fBdefault_ttl\fR module option. Default ip
hash size is 256 and can be changed using \fBhash_size\fR module option.
.TP
\fB\-\-prefix\fR \fIaddr\fR\fB/\fR\fImask\fR
Network subnet to map to. If not specified, all existing prefixes are used.
@@ -35,7 +35,7 @@ bindings ttl is kept unchanged. If not specified then default ttl value (600s)
is used.
.PP
\fB* /proc interface\fR
.PP
Module creates following entries for each new specified subnet:
.TP
\fB/proc/net/xt_DNETMAP/\fR\fIsubnet\fR\fB_\fR\fImask\fR
@@ -80,71 +80,70 @@ and are available for dynamic bindings.
Note! Entries are removed if the last iptables rule for a specific prefix is
deleted unless there's persistent flag set.
.PP
\fB* Logging\fR
.PP
Module logs binding add/timeout events to klog. This behaviour can be disabled
using \fBdisable_log\fR module parameter.
.PP
\fB* Examples\fR
.PP
\fB1.\fR Map subnet 192.168.0.0/24 to subnets 20.0.0.0/26. SNAT only:
.PP
iptables \-t nat \-A POSTROUTING \-s 192.168.0.0/24 \-j DNETMAP \-\-prefix 20.0.0.0/26
.PP
Active hosts from 192.168.0.0/24 subnet are mapped to 20.0.0.0/26. If packet
from not yet bound prenat-ip hits the rule and there are no free or timed-out
(ttl<0) entries in prefix 20.0.0.0/28, then notice is logged to klog and chain
traversal continues. If packet from already bound prenat-ip hits the rule,
bindings ttl value is regenerated to default_ttl and SNAT is performed.
.PP
\fB2.\fR Use of \fB\-\-reuse\fR and \fB\-\-ttl\fR switches, multiple rule
interaction:
.PP
iptables \-t nat \-A POSTROUTING \-s 192.168.0.0/24 \-j DNETMAP \-\-prefix
20.0.0.0/26 \-\-reuse \-\-ttl 200
.PP
iptables \-t nat \-A POSTROUTING \-s 192.168.0.0/24 \-j DNETMAP \-\-prefix 30.0.0.0/26
.PP
Active hosts from 192.168.0.0/24 subnet are mapped to 20.0.0.0/26 with ttl =
200 seconds. If there are no free addresses in first prefix the next one
(30.0.0.0/26) is used with default ttl. It's important to note that the first
rule SNATs all flows whose source IP is already actively (ttl>0) bound to ANY
prefix. Parameter \fB\-\-reuse\fR makes this functionality work even for
inactive (ttl<0) entries.
.PP
If both subnets are exhaused, then chain traversal continues.
.PP
\fB3.\fR Map 192.168.0.0/24 to subnets 20.0.0.0/26 bidirectional way:
.PP
iptables \-t nat \-A POSTROUTING \-s 192.168.0.0/24 \-j DNETMAP \-\-prefix 20.0.0.0/26
.PP
iptables \-t nat \-A PREROUTING \-j DNETMAP
.PP
If host 192.168.0.10 generates some traffic, it gets bound to first free IP in
subnet - 20.0.0.0. Now any traffic directed to 20.0.0.0 gets DNATed to
192.168.0.10 as long as there's an active (ttl>0) binding. There's no need to
specify \fB\-\-prefix\fR parameter in PREROUTING rule, because this way it DNATs
traffic to all active prefixes. You could specify prefix it you'd like to make
DNAT work for specific prefix only.
.PP
\fB4.\fR Map 192.168.0.0/24 to subnets 20.0.0.0/26 with static assignments only:
.PP
iptables \-t nat \-A POSTROUTING \-s 192.168.0.0/24 \-j DNETMAP \-\-prefix 20.0.0.0/26
\-\-static
.PP
echo "+192.168.0.10:20.0.0.1" > /proc/net/xt_DNETMAP/20.0.0.0_26
.br
echo "+192.168.0.11:20.0.0.2" > /proc/net/xt_DNETMAP/20.0.0.0_26
.br
echo "+192.168.0.51:20.0.0.3" > /proc/net/xt_DNETMAP/20.0.0.0_26
.PP
This configuration will allow only preconfigured static bindings to work due to
\fBstatic\fR rule option. Without this flag dynamic bindings would be created
using non-static entries.
.PP
\fB5.\fR Persistent prefix:
.PP
iptables \-t nat \-A POSTROUTING \-s 192.168.0.0/24 \-j DNETMAP \-\-prefix 20.0.0.0/26
\-\-persistent
.br
@@ -153,13 +152,13 @@ iptables \-t nat \-A POSTROUTING \-s 192.168.0.0/24 \-j DNETMAP \-\-prefix 20.0.
iptables \-t nat \-A POSTROUTING \-s 192.168.0.0/24 \-j DNETMAP \-\-prefix 20.0.0.0/26
.br
echo "+persistent" > /proc/net/xt_DNETMAP/20.0.0.0_26
.PP
Now we can check persistent flag of the prefix:
.br
cat /proc/net/xt_DNETMAP/20.0.0.0_26
.br
0 0 64 0 \fBpersistent\fR
.PP
Flush iptables nat table and see that prefix is still in existence:
.br
iptables \-F \-t nat

1
extensions/libxt_ECHO.man
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@@ -1,3 +1,4 @@
.PP
The \fBECHO\fP target will send back all packets it received. It serves as an
examples for an Xtables target.
.PP

3
extensions/libxt_IPMARK.man
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@@ -1,7 +1,8 @@
.PP
Allows you to mark a received packet basing on its IP address. This
can replace many mangle/mark entries with only one, if you use
firewall based classifier.
.PP
This target is to be used inside the \fBmangle\fP table.
.TP
\fB\-\-addr\fP {\fBsrc\fP|\fBdst\fP}

1
extensions/libxt_LOGMARK.man
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@@ -1,3 +1,4 @@
.PP
The LOGMARK target will log packet and connection marks to syslog.
.TP
\fB\-\-log\-level\fR \fIlevel\fR

1
extensions/libxt_RAWDNAT.man
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@@ -1,3 +1,4 @@
.PP
The \fBRAWDNAT\fR target will rewrite the destination address in the IP header,
much like the \fBNETMAP\fR target.
.TP

1
extensions/libxt_RAWSNAT.man
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@@ -1,3 +1,4 @@
.PP
The \fBRAWSNAT\fR and \fBRAWDNAT\fP targets provide stateless network address
translation.
.PP

1
extensions/libxt_STEAL.man
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@@ -1,2 +1,3 @@
.PP
Like the DROP target, but does not throw an error like DROP when used in the
\fBOUTPUT\fP chain.

1
extensions/libxt_SYSRQ.man
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@@ -1,3 +1,4 @@
.PP
The SYSRQ target allows to remotely trigger sysrq on the local machine over the
network. This can be useful when vital parts of the machine hang, for example
an oops in a filesystem causing locks to be not released and processes to get

1
extensions/libxt_TARPIT.man
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@@ -1,3 +1,4 @@
.PP
Captures and holds incoming TCP connections using no local per-connection
resources.
.PP

1
extensions/libxt_condition.man
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@@ -1,3 +1,4 @@
.PP
This matches if a specific condition variable is (un)set.
.TP
[\fB!\fP] \fB\-\-condition\fP \fIname\fP

1
extensions/libxt_fuzzy.man
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@@ -1,3 +1,4 @@
.PP
This module matches a rate limit based on a fuzzy logic controller (FLC).
.TP
\fB\-\-lower\-limit\fP \fInumber\fP

1
extensions/libxt_geoip.man
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@@ -1,3 +1,4 @@
.PP
Match a packet by its source or destination country.
.TP
[\fB!\fP] \fB\-\-src\-cc\fP, \fB\-\-source\-country\fP \fIcountry\fP[\fB,\fP\fIcountry\fP\fB...\fP]

1
extensions/libxt_gradm.man
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@@ -1,3 +1,4 @@
.PP
This module matches packets based on grsecurity RBAC status.
.TP
[\fB!\fP] \fB\-\-enabled\fP

1
extensions/libxt_iface.man
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@@ -1,3 +1,4 @@
.PP
Allows you to check interface states. First, an interface needs to be selected
for comparison. Exactly one option of the following three must be specified:
.TP

1
extensions/libxt_ipp2p.man
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@@ -1,3 +1,4 @@
.PP
This module matches certain packets in P2P flows. It is not
designed to match all packets belonging to a P2P connection \(em
use IPP2P together with CONNMARK for this purpose.

1
extensions/libxt_ipv4options.man
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@@ -1,3 +1,4 @@
.PP
The "ipv4options" module allows to match against a set of IPv4 header options.
.TP
\fB\-\-flags\fP [\fB!\fP]\fIsymbol\fP[\fB,\fP[\fB!\fP]\fIsymbol...\fP]

1
extensions/libxt_length2.man
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@@ -1,3 +1,4 @@
.PP
This module matches the length of a packet against a specific value or range of
values.
.TP

1
extensions/libxt_lscan.man
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@@ -1,3 +1,4 @@
.PP
Detects simple low-level scan attempts based upon the packet's contents.
(This is
different from other implementations, which also try to match the rate of new

1
extensions/libxt_psd.man
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@@ -1,3 +1,4 @@
.PP
Attempt to detect TCP and UDP port scans. This match was derived from
Solar Designer's scanlogd.
.TP

1
extensions/libxt_quota2.man
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@@ -1,3 +1,4 @@
.PP
The "quota2" implements a named counter which can be increased or decreased
on a per-match basis. Available modes are packet counting or byte counting.
The value of the counter can be read and reset through procfs, thereby making