Content-type: text/html Man page of IPSET

IPSET

Section: (8)
Updated: Aug 28, 2007
Index

NAME

ipset - administration tool for IP sets

SYNOPSIS

ipset -N set type-specification [options]
ipset -[XFLSHh] [set] [options]
ipset -[EW] from-set to-set
ipset -[ADU] set entry
ipset -B set entry -b binding
ipset -T set entry [-b binding]
ipset -R

DESCRIPTION

ipset is used to set up, maintain and inspect so called IP sets in the Linux kernel. Depending on the type, an IP set may store IP addresses, (TCP/UDP) port numbers or additional informations besides IP addresses: the word IP means a general term here. See the set type definitions below. Any entry in a set can be bound to another set, which forms a relationship between a set element and the set it is bound to. In order to define a binding it is not required that the entry be already added to the set. The sets may have a default binding, which is valid for every set element for which there is no binding defined at all. IP set bindings pointing to sets and iptables matches and targets referring to sets creates references, which protects the given sets in the kernel. A set cannot be removed (destroyed) while there is a single reference pointing to it.

OPTIONS

The options that are recognized by ipset can be divided into several different groups.

COMMANDS

These options specify the specific action to perform. Only one of them can be specified on the command line unless otherwise specified below. For all the long versions of the command and option names, you need to use only enough letters to ensure that ipset can differentiate it from all other options.

-N, --create setname type type-specific-options: Create a set identified with setname and specified type. Type-specific options must be supplied.
-X, --destroy [setname]: Destroy the specified set, or all sets if none or the keyword :all: is specified. Before destroying the set, all bindings belonging to the set elements and the default binding of the set are removed.
If the set has got references, nothing is done.
-F, --flush [setname]: Delete all entries from the specified set, or flush all sets if none or the keyword :all: is given. Bindings are not affected by the flush operation.
-E, --rename from-setname to-setname: Rename a set. Set identified by to-setname must not exist.
-W, --swap from-setname to-setname: Swap two sets as they referenced in the Linux kernel. iptables rules or ipset bindings pointing to the content of from-setname will point to the content of to-setname and vice versa. Both sets must exist.
-L, --list [setname]: List the entries and bindings for the specified set, or for all sets if none or the keyword :all: is given. The -n, --numeric option can be used to suppress name lookups and generate numeric output. When the -s, --sorted option is given, the entries are listed sorted (if the given set type supports the operation).
-S, --save [setname]: Save the given set, or all sets if none or the keyword :all: is specified to stdout in a format that --restore can read.
-R, --restore: Restore a saved session generated by --save. The saved session can be fed from stdin.
When generating a session file please note that the supported commands (create set, add element, bind) must appear in a strict order: first create the set, then add all elements. Then create the next set, add all its elements and so on. Finally you can list all binding commands. Also, it is a restore operation, so the sets being restored must not exist.
-A, --add setname IP: Add an IP to a set.
-D, --del setname IP: Delete an IP from a set.
-T, --test setname IP: Test wether an IP is in a set or not. Exit status number is zero if the tested IP is in the set and nonzero if it is missing from the set.
-T, --test setname IP --binding to-setname: Test wether the IP belonging to the set points to the specified binding. Exit status number is zero if the binding points to the specified set, otherwise it is nonzero. The keyword :default: can be used to test the default binding of the set.
-B, --bind setname IP --binding to-setname: Bind the IP in setname to to-setname.
-U, --unbind setname IP: Delete the binding belonging to IP in set setname.
-H, --help [settype]: Print help and settype specific help if settype specified.

At the -B, -U and -T commands you can use the token :default: to bind, unbind or test the default binding of a set instead of an IP. At the -U command you can use the token :all: to destroy the bindings of all elements of a set.

OTHER OPTIONS

The following additional options can be specified:

-b, --binding setname: The option specifies the value of the binding for the -B binding command, for which it is a mandatory option. You can use it in the -T test command as well to test bindings.
-s, --sorted: Sorted output. When listing sets, entries are listed sorted.
-n, --numeric: Numeric output. When listing sets, bindings, IP addresses and port numbers will be printed in numeric format. By default the program will try to display them as host names, network names or services (whenever applicable), which can trigger slow DNS lookups.
-q, --quiet: Suppress any output to stdout and stderr. ipset will still return possible errors.

SET TYPES

ipset supports the following set types:

ipmap

The ipmap set type uses a memory range, where each bit represents one IP address. An ipmap set can store up to 65536 (B-class network) IP addresses. The ipmap set type is very fast and memory cheap, great for use when one want to match certain IPs in a range. Using the --netmask option with a CIDR netmask value between 0-32 when creating an ipmap set, you will be able to store and match network addresses: i.e an IP address will be in the set if the value resulted by masking the address with the specified netmask can be found in the set.

Options to use when creating an ipmap set:

--from from-IP
--to to-IP: Create an ipmap set from the specified range.
--network IP/mask: Create an ipmap set from the specified network.
--netmask CIDR-netmask: When the optional --netmask parameter specified, network addresses will be stored in the set instead of IP addresses, and the from-IP parameter must be a network address.

macipmap

The macipmap set type uses a memory range, where each 8 bytes represents one IP and a MAC addresses. A macipmap set type can store up to 65536 (B-class network) IP addresses with MAC. When adding an entry to a macipmap set, you must specify the entry as IP:MAC. When deleting or testing macipmap entries, the :MAC part is not mandatory. (The old "%" separation token instead of ":", i.e IP%MAC is accepted as well.)

Options to use when creating an macipmap set:

--from from-IP
--to to-IP: Create a macipmap set from the specified range.
--network IP/mask: Create a macipmap set from the specified network.
--matchunset: When the optional --matchunset parameter specified, IP addresses which could be stored in the set but not set yet, will always match.

Please note, the set and SET netfilter kernel modules always use the source MAC address from the packet to match, add or delete entries from a macipmap type of set.

portmap

The portmap set type uses a memory range, where each bit represents one port. A portmap set type can store up to 65536 ports. The portmap set type is very fast and memory cheap.

Options to use when creating an portmap set:

--from from-port
--to to-port: Create a portmap set from the specified range.

iphash

The iphash set type uses a hash to store IP addresses. In order to avoid clashes in the hash double-hashing, and as a last resort, dynamic growing of the hash performed. The iphash set type is great to store random addresses. By supplyig the --netmask option with a CIDR netmask value between 0-32 at creating the set, you will be able to store and match network addresses instead: i.e an IP address will be in the set if the value of the address masked with the specified netmask can be found in the set.

Options to use when creating an iphash set:

--hashsize hashsize: The initial hash size (default 1024)
--probes probes: How many times try to resolve clashing at adding an IP to the hash by double-hashing (default 8).
--resize percent: Increase the hash size by this many percent (default 50) when adding an IP to the hash could not be performed after probes number of double-hashing.
--netmask CIDR-netmask: When the optional --netmask parameter specified, network addresses will be stored in the set instead of IP addresses.

The iphash type of sets can store up to 65535 entries. If a set is full, no new entries can be added to it.

Sets created by zero valued resize parameter won't be resized at all. The lookup time in an iphash type of set approximately linearly grows with the value of the probes parameter. At the same time higher probes values result a better utilized hash while smaller values produce a larger, sparse hash.

nethash

The nethash set type uses a hash to store different size of network addresses. The IP "address" used in the ipset commands must be in the form IP-address/cidr-size where the CIDR block size must be in the inclusive range of 1-31. In order to avoid clashes in the hash double-hashing, and as a last resort, dynamic growing of the hash performed.

Options to use when creating an nethash set:

--hashsize hashsize: The initial hash size (default 1024)
--probes probes: How many times try to resolve clashing at adding an IP to the hash by double-hashing (default 4).
--resize percent: Increase the hash size by this many percent (default 50) when adding an IP to the hash could not be performed after

The nethash type of sets can store up to 65535 entries. If a set is full, no new entries can be added to it.

An IP address will be in a nethash type of set if it is in any of the netblocks added to the set and the matching always start from the smallest size of netblock (most specific netmask) to the biggest ones (least specific netmasks). When adding/deleting IP addresses to a nethash set by the SET netfilter kernel module, it will be added/deleted by the smallest netblock size which can be found in the set. The lookup time in a nethash type of set is approximately linearly grows with the times of the probes parameter and the number of different mask parameters in the hash. Otherwise the same speed and memory efficiency comments applies here as at the iphash type.

ipporthash

The ipporthash set type uses a hash to store IP address and port pairs. In order to avoid clashes in the hash double-hashing, and as a last resort, dynamic growing of the hash performed. An ipporthash set can store up to 65536 (B-class network) IP addresses with all possible port values. When adding, deleting and testing values in an ipporthash type of set, the entries must be specified as "IP:port". (Old "IP%port" format accepted as well.)

The ipporthash types of sets evaluates two src/dst parameters of the set match and SET target.

Options to use when creating an ipporthash set:

--from from-IP
--to to-IP: Create an ipporthash set from the specified range.
--network IP/mask: Create an ipporthash set from the specified network.
--hashsize hashsize: The initial hash size (default 1024)
--probes probes: How many times try to resolve clashing at adding an IP to the hash by double-hashing (default 8).
--resize percent: Increase the hash size by this many percent (default 50) when adding an IP to the hash could not be performed after probes number of double-hashing.

The same resizing, speed and memory efficiency comments applies here as at the iphash type.

iptree

The iptree set type uses a tree to store IP addresses, optionally with timeout values.

Options to use when creating an iptree set:

--timeout value: The timeout value for the entries in seconds (default 0)

If a set was created with a nonzero valued --timeout parameter then one may add IP addresses to the set with a specific timeout value using the syntax IP:timeout-value.

Similarly to the hash types, the iptree type of sets can store up to 65535 entries.

iptreemap

The iptreemap set type uses a tree to store IP addresses or networks, where the last octet of an IP address are stored in a bitmap. As input entry, you can add IP addresses, CIDR blocks or network ranges to the set. Network ranges can be specified in the format IP1:IP2

Options to use when creating an iptreemap set:

--gc value: How often the garbage collection should be called, in seconds (default 300)

GENERAL RESTRICTIONS

Setnames starting with colon (:) cannot be defined. Zero valued set entries cannot be used with hash type of sets.

COMMENTS

If you want to store same size subnets from a given network (say /24 blocks from a /8 network), use the ipmap set type. If you want to store random same size networks (say random /24 blocks), use the iphash set type. If you have got random size of netblocks, use nethash.

DIAGNOSTICS

Various error messages are printed to standard error. The exit code is 0 for correct functioning. Errors which appear to be caused by invalid or abused command line parameters cause an exit code of 2, and other errors cause an exit code of 1.