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IPSECADM(8) OpenBSD System Manager's Manual IPSECADM(8) NAME ipsecadm - interface to set up IPsec SYNOPSIS ipsecadm [command] modifiers ... NOTE To use ipsecadm, IPsec must be enabled by having one or more of the fol- lowing sysctl(3) variables set: net.inet.esp.enable Enable the ESP IPsec protocol net.inet.ah.enable Enable the AH IPsec protocol net.inet.ipcomp.enable Enable the IPComp protocol Both the ESP and AH protocols are enabled by default. To keep local mod- ifications of these variables across reboots, see sysctl.conf(5). DESCRIPTION The ipsecadm utility sets up security associations in the kernel to be used with ipsec(4). It can be used to specify the encryption and authen- tication algorithms and key material for the network layer security pro- vided by IPsec. The possible commands are: new esp Set up a Security Association (SA) which uses the new esp trans- forms. A SA consists of the destination address, a Security Pa- rameter Index (SPI) and a security protocol. Encryption and au- thentication algorithms can be applied. This is the default mode. Allowed modifiers are: -dst, -src, -proxy, -spi, -enc, -srcid_type, -srcid, -dstid_type, -dstid, -auth, -authkey, -authkeyfile, -forcetunnel, -key, and -keyfile. old esp Set up an SA which uses the old esp transforms. Only encryption algorithms can be applied. Allowed modifiers are: -dst, -src, -proxy, -spi, -enc, -srcid_type, -srcid, -dstid_type, -dstid, -halfiv, -forcetunnel, -key, and -keyfile. new ah Set up an SA which uses the new ah transforms. Authentication will be done with HMAC using the specified hash algorithm. Al- lowed modifiers are: -dst, -src, -proxy, -spi, -srcid_type, -srcid, -dstid_type, -dstid, -forcetunnel, -auth, -key, and -keyfile. old ah Set up an SA which uses the old ah transforms. Simple keyed hashes will be used for authentication. Allowed modifiers are: -dst, -src, -proxy, -spi, -srcid_type, -srcid, -dstid_type, -dstid, -forcetunnel, -auth, -key, and -keyfile. group Group two SAs together, such that whenever the first one is ap- plied, the second one will be applied as well (SA bundle). Ar- bitrarily long SA bundles can thus be created. Note that the last SA in the bundle is the one that is applied last. Thus, if an ESP and an AH SA are bundled together (in that order), then the resulting packet will have an AH header, followed by an ESP header, followed by the encrypted payload. Allowed modifiers are: -dst, -spi, -proto, -dst2, -spi2, and -proto2. ip4 Set up an SA which uses the IP-in-IP encapsulation protocol. This mode offers no security services by itself, but can be used to route other (experimental or otherwise) protocols over an IP network. The SPI value is not used for anything other than ref- erencing the information, and does not appear on the wire. Un- like other setups, like new esp, there is no necessary setup in the receiving side. Allowed modifiers are: -dst, -src, and -spi. delspi The specified SA will be deleted. Allowed modifiers are: -dst, -spi, and -proto. flow Create a flow determining what security parameters a packet should have (input or output). Allowed modifiers are: -src, -dst, -proto, -addr, -transport, -sport, -dport, -delete, -in, -out, -srcid, -dstid, -srcid_type, -dstid_type, -acquire, -require, -dontacq, -use, -bypass, -permit and -deny. The net- stat(1) command shows all specified flows. Flows are direction- al, and the -in and -out modifiers are used to specify the di- rection. By default, flows are assumed to apply to outgoing packets. The kernel will attempt to find an appropriate Securi- ty Association from those already present (an SA that matches the destination address, if set, and the security protocol). If the destination address is set to all zeroes (0.0.0.0) or left unspecified, the destination address from the packet will be used to locate an SA (the source address is used for incoming flows). For incoming flows, the destination address (if speci- fied) should point to the expected source of the SA (the remote SA peer). If no such SA exists, key management daemons will be used to generate them if -acquire or -require were used. If -acquire was used, traffic will be allowed out (or in) and IPsec will be used when the relevant SAs have been established. If -require was used, traffic will not be allowed in or out until it is protected by IPsec. If -dontacq was used, traffic will not be allowed in or out until it is protected by IPsec, but key management will not be asked to provide such an SA. The -proto argument (by default set to esp) will be used to determine what type of SA should be established. A bypass or permit flow is used to specify a flow for which IPsec processing will be by- passed, i.e packets will/need not be processed by any SAs. For bypass or permit flows, additional modifiers are restricted to: -addr, -transport, -sport, -dport, -in, -out, and -delete. A deny flow is used to specify classes of packets that must be dropped (either on output or input) without further processing. deny takes the same additional modifiers as bypass. flush Flush SAs from kernel. This includes flushing any flows and routing entries associated with the SAs. Allowed modifiers are: -ah, -esp, -oldah, -oldesp, -ip4, and -ipcomp. Default action is to flush all types of security associations from the kernel. show Show SAs from kernel. Allowed modifiers are: -ah, -esp, -oldah, -oldesp, -ip4, and -ipcomp. Default action is to show all types of security associations from the kernel. monitor Continuously display all PF_KEY messages exchanged with the ker- nel. ipcomp Set up an IP Compression Association (IPCA) which will use the IPcomp transforms. Just like an SA, an IPCA consists of the destination address, a Compression Parameter Index (CPI) and a protocol (which is fixed to IPcomp). Compression algorithms are applied. Allowed modifiers are: -dst, -src, -cpi, -comp, and -forcetunnel. To create an IPsec SA using compression, an IPCA and an SA must first be created. After this an IPCA/SA bundle must be created using the group keyword. The IPCA must be ap- plied first. If no command is given ipsecadm defaults to new esp mode. The modifiers have the following meanings: -src The source IP address for the SA. This is necessary for in- coming SAs to avoid source address spoofing between mutually suspicious hosts that have established SAs with us. For out- going SAs, this field is used to fill in the source address when doing tunneling. -dst The destination IP address for the SA. -dst2 The second IP address used by group. -proxy This IP address, if provided, is checked against the inner IP address when doing tunneling to a firewall, to prevent source spoofing attacks. It is strongly recommended that this op- tion is provided when applicable. It is applicable in a sce- nario when host A is using IPsec to communicate with firewall B, and through that to host C. In that case, the proxy ad- dress for the incoming SA should be C. This option is not necessary for outgoing SAs. -spi The Security Parameter Index (SPI), given as a hexadecimal number. -spi2 The second SPI used by group. -cpi The Compression Parameter Index (CPI), given as a 16 bit hex- adecimal number. -tunnel This option has been deprecated. The arguments are ignored, and it otherwise has the same effect as the forcetunnel op- tion. -newpadding This option has been deprecated. -forcetunnel Force IP-inside-IP encapsulation before ESP or AH processing is performed for outgoing packets. The source/destination addresses of the outgoing IP packet will be those provided in the src and dst options. Notice that the IPsec stack will perform IP-inside-IP encapsulation when deemed necessary, even if this flag has not been set. -enc The encryption algorithm to be used with the SA. Possible values are: des This is available for both old and new esp. Notice that hardware crackers for DES can be (and have been) built for US$250,000 (in 1998). Use DES for encryption of critical information at your own risk. We suggest using 3DES or AES instead. DES support is kept for interoperability (with old im- plementations) purposes only. See des_cipher(3). 3des This is available for both old and new esp. It is considered more secure than straight DES, since it uses larger keys. aes Rijndael encryption is available only in new esp. blf Blowfish encryption is available only in new esp. See blf_key(3). cast CAST encryption is available only in new esp. skipjack SKIPJACK encryption is available only in new esp. This algorithm was designed by the NSA and is faster than 3DES. However, since it was designed by the NSA it is a poor choice. -auth The authentication algorithm to be used with the SA. Possi- ble values are: md5 and sha1 for both old and new ah and also new esp. Also rmd160, sha2-256, sha2-384, sha2-512 for both new ah and esp. -comp The compression algorithm to be used with the IPCA. Possible values are: deflate and lzs. Note that lzs is only available with hifn(4) because of the patent held by Hifn, Inc. -key The secret symmetric key used for encryption and authentica- tion. The size for des and 3des is fixed to 8 and 24 respec- tively. For other ciphers like cast, aes, or blf the key length can vary (depending on the algorithm). The key should be given in hexadecimal digits. The key should be chosen at random (ideally, using some true-random source like coin flipping). It is very important that the key is not guess- able. One practical way of generating 160-bit (20-byte) keys is as follows: $ openssl rand 20 | hexdump -e '20/1 "%02x"' -keyfile Read the key from a file. May be used instead of the -key flag, and has the same syntax considerations. -authkey The secret key material used for authentication if additional authentication in new esp mode is required. For old or new ah the key material for authentication is passed with the key option. The key should be given in hexadecimal digits. The key should be chosen at random (ideally, using some true-ran- dom source like coin flipping). It is very important that the key is not guessable. One practical way of generating 160-bit (20-byte) keys is as follows: $ openssl rand 20 | hexdump -e '20/1 "%02x"' -authkeyfile Read the authkey from a file. May be used instead of the -authkey flag, and has the same syntax considerations. -iv This option has been deprecated. The argument is ignored. When applicable, it has the same behaviour as the halfiv op- tion. -halfiv This option causes use of a 4 byte IV in old ESP (as opposed to 8 bytes). It may only be used with old ESP. -proto The security protocol needed by delspi or flow, to uniquely specify the SA. The default value is 50 which means IPPROTO_ESP. Other accepted values are 51 (IPPROTO_AH), and 4 (IPPROTO_IP). One can also specify the symbolic names "esp", "ah", and "ip4", case insensitive. -proto2 The second security protocol used by group. It defaults to IPPROTO_AH, otherwise takes the same values as -proto. -addr The source address, source network mask, destination address and destination network mask against which packets need to match to use the specified Security Association. Alterna- tively, addresses and masks can be specified as ``source/prefixlen destination/prefixlen''. All addresses must be of the same address family (IPv4 or IPv6). -transport The protocol number which packets need to match to use the specified Security Association. By default the protocol num- ber is not used for matching. Instead of a number, a valid protocol name that appears in protocols(5) can be used. -sport The source port which packets have to match for the flow. By default the source port is not used for matching. Instead of a number, a valid service name that appears in services(5) can be used. -dport The destination port which packets have to match for the flow. By default the source port is not used for matching. Instead of a number, a valid service name that appears in services(5) can be used. -srcid For flow, used to specify what local identity key management should use when negotiating the SAs. If left unspecified, the source address of the flow is used (see the discussion on flow above, with regard to source address). -dstid For flow, used to specify what the remote identity key man- agement should expect is. If left unspecified, the destina- tion address of the flow is used (see the discussion on flow above, with regard to destination address). -srcid_type For flow, used to specify the type of identity given by -srcid. Valid values are prefix, fqdn, and ufqdn. The prefix type implies an IPv4 or IPv6 address followed by a forward slash character and a decimal number indicating the number of important bits in the address (equivalent to a net- mask, in IPv4 terms). Key management then has to pick a lo- cal identity that falls within the address space indicated. The fqdn and ufqdn types are DNS-style host names and mail- box-format user addresses, respectively, and are especially useful for mobile user scenarios. Note that no validity checking on the identities is done. -dstid_type See -srcid_type. -delete Instead of creating a flow, an existing flow is deleted. -bypass For flow, create or delete a bypass flow. Packets matching this flow will not be processed by IPsec. -permit Same as -bypass. -deny For flow, create or delete a deny flow. Packets matching this flow will be dropped. -use For flow, specify that packets matching this flow should try to use IPsec if possible. -acquire For flow, specify that packets matching this flow should try to use IPsec and establish SAs dynamically if possible, but permit unencrypted traffic. -require For flow, specify that packets matching this flow must use IPsec, and establish SAs dynamically as needed. If no SAs are established, traffic is not allowed through. -dontacq For flow, specify that packets matching this flow must use IPsec. If such SAs are not present, simply drop the packets. Such a policy may be used to demand peers establish SAs be- fore they can communicate with us, without going through the burden of initiating the SA ourselves (thus allowing for some denial of service attacks). This flow type is particularly suitable for security gateways. -in For flow, specify that it should be used to match incoming packets only. -out For flow, specify that it should be used to match outgoing packets only. -ah For flush, only flush SAs of type ah. -esp For flush, only flush SAs of type esp. -oldah For flush, only flush SAs of type old ah. -oldesp For flush, only flush SAs of type old esp. -ip4 For flush, only flush SAs of type ip4. EXAMPLES Set up an SA which uses new esp with 3des encryption and HMAC-SHA1 au- thentication: # ipsecadm new esp -enc 3des -auth sha1 -spi 100a -dst 169.20.12.2 \ -src 169.20.12.3 \ -key 638063806380638063806380638063806380638063806380 \ -authkey 1234123412341234123412341234123412341234 Set up an SA for authentication with old ah only: # ipsecadm old ah -auth md5 -spi 10f2 -dst 169.20.12.2 -src 169.20.12.3 \ -key 12341234deadbeef Set up a flow requiring use of AH: # ipsecadm flow -dst 169.20.12.2 -proto ah \ -addr 10.1.1.0/24 10.0.0.0/24 -out -require Set up an inbound SA: # ipsecadm new esp -enc blf -auth md5 -spi 1002 -dst 169.20.12.3 \ -src 169.20.12.2 \ -key abadbeef15deadbeefabadbeef15deadbeefabadbeef15deadbeef \ -authkey 12349876432167890192837465098273 Set up an ingress flow for the inbound SA: # ipsecadm flow -addr 10.0.0.0/8 10.1.1.0/24 \ -dst 169.20.12.2 -proto esp -in -require Set up a bypass flow: # ipsecadm flow -bypass -out \ -addr 10.1.1.0/24 10.1.1.0/24 Delete all esp SAs and their flows and routing information: # ipsecadm flush -esp SEE ALSO netstat(1), enc(4), ipsec(4), protocols(5), services(5), sysctl.conf(5), isakmpd(8), vpn(8) OpenBSD 3.4 August 26, 1997 7
NAME | SYNOPSIS | NOTE | DESCRIPTION | EXAMPLES | SEE ALSO
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