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 IETF CIPSO Working Group
 16 July, 1992
 
 
 
                  COMMERCIAL IP SECURITY OPTION (CIPSO 2.2)
 
 
 
 1.    Status
 
 This Internet Draft provides the high level specification for a Commercial
 IP Security Option (CIPSO).  This draft reflects the version as approved by
 the CIPSO IETF Working Group.  Distribution of this memo is unlimited.
 
 This document is an Internet Draft.  Internet Drafts are working documents
 of the Internet Engineering Task Force (IETF), its Areas, and its Working
 Groups. Note that other groups may also distribute working documents as
 Internet Drafts.
 
 Internet Drafts are draft documents valid for a maximum of six months.
 Internet Drafts may be updated, replaced, or obsoleted by other documents
 at any time.  It is not appropriate to use Internet Drafts as reference
 material or to cite them other than as a "working draft" or "work in
 progress."
 
 Please check the I-D abstract listing contained in each Internet Draft
 directory to learn the current status of this or any other Internet Draft.
 
 
 
 
 2.    Background
 
 Currently the Internet Protocol includes two security options.  One of
 these options is the DoD Basic Security Option (BSO) (Type 130) which allows
 IP datagrams to be labeled with security classifications.  This option
 provides sixteen security classifications and a variable number of handling
 restrictions.  To handle additional security information, such as security
 categories or compartments, another security option (Type 133) exists and
 is referred to as the DoD Extended Security Option (ESO).  The values for
 the fixed fields within these two options are administered by the Defense
 Information Systems Agency (DISA).
 
 Computer vendors are now building commercial operating systems with
 mandatory access controls and multi-level security.  These systems are
 no longer built specifically for a particular group in the defense or
 intelligence communities.  They are generally available commercial systems
 for use in a variety of government and civil sector environments.
 
 The small number of ESO format codes can not support all the possible
 applications of a commercial security option.  The BSO and ESO were
 designed to only support the United States DoD.  CIPSO has been designed
 to support multiple security policies.  This Internet Draft provides the
 format and procedures required to support a Mandatory Access Control
 security policy.  Support for additional security policies shall be
 defined in future RFCs.
 
 
 
 
 Internet Draft, Expires 15 Jan 93                                 [PAGE 1]
 
 
 
 CIPSO INTERNET DRAFT                                         16 July, 1992
 
 
 
 
 3.    CIPSO Format
 
 Option type: 134 (Class 0, Number 6, Copy on Fragmentation)
 Option length: Variable
 
 This option permits security related information to be passed between
 systems within a single Domain of Interpretation (DOI).  A DOI is a
 collection of systems which agree on the meaning of particular values
 in the security option.  An authority that has been assigned a DOI
 identifier will define a mapping between appropriate CIPSO field values
 and their human readable equivalent.  This authority will distribute that
 mapping to hosts within the authority's domain.  These mappings may be
 sensitive, therefore a DOI authority is not required to make these
 mappings available to anyone other than the systems that are included in
 the DOI.
 
 This option MUST be copied on fragmentation.  This option appears at most
 once in a datagram.  All multi-octet fields in the option are defined to be
 transmitted in network byte order.  The format of this option is as follows:
 
 +----------+----------+------//------+-----------//---------+
 | 10000110 | LLLLLLLL | DDDDDDDDDDDD | TTTTTTTTTTTTTTTTTTTT |
 +----------+----------+------//------+-----------//---------+
 
   TYPE=134    OPTION    DOMAIN OF               TAGS
               LENGTH    INTERPRETATION
 
 
                 Figure 1. CIPSO Format
 
 
 3.1    Type
 
 This field is 1 octet in length.  Its value is 134.
 
 
 3.2    Length
 
 This field is 1 octet in length.  It is the total length of the option
 including the type and length fields.  With the current IP header length
 restriction of 40 octets the value of this field MUST not exceed 40.
 
 
 3.3    Domain of Interpretation Identifier
 
 This field is an unsigned 32 bit integer.  The value 0 is reserved and MUST
 not appear as the DOI identifier in any CIPSO option.  Implementations
 should assume that the DOI identifier field is not aligned on any particular
 byte boundary.
 
 To conserve space in the protocol, security levels and categories are
 represented by numbers rather than their ASCII equivalent.  This requires
 a mapping table within CIPSO hosts to map these numbers to their
 corresponding ASCII representations.  Non-related groups of systems may
 
 
 
 Internet Draft, Expires 15 Jan 93                                 [PAGE 2]
 
 
 
 CIPSO INTERNET DRAFT                                         16 July, 1992
 
 
 
 have their own unique mappings.  For example, one group of systems may
 use the number 5 to represent Unclassified while another group may use the
 number 1 to represent that same security level.  The DOI identifier is used
 to identify which mapping was used for the values within the option.
 
 
 3.4    Tag Types
 
 A common format for passing security related information is necessary
 for interoperability.  CIPSO uses sets of "tags" to contain the security
 information relevant to the data in the IP packet.  Each tag begins with
 a tag type identifier followed by the length of the tag and ends with the
 actual security information to be passed.  All multi-octet fields in a tag
 are defined to be transmitted in network byte order.  Like the DOI
 identifier field in the CIPSO header, implementations should assume that
 all tags, as well as fields within a tag, are not aligned on any particular
 octet boundary.   The tag types defined in this document contain alignment
 bytes to assist alignment of some information, however alignment can not
 be guaranteed if CIPSO is not the first IP option.
 
 CIPSO tag types 0 through 127 are reserved for defining standard tag
 formats.  Their definitions will be published in RFCs.  Tag types whose
 identifiers are greater than 127 are defined by the DOI authority and may
 only be meaningful in certain Domains of Interpretation.  For these tag
 types, implementations will require the DOI identifier as well as the tag
 number to determine the security policy and the format associated with the
 tag.  Use of tag types above 127 are restricted to closed networks where
 interoperability with other networks will not be an issue.  Implementations
 that support a tag type greater than 127 MUST support at least one DOI that
 requires only tag types 1 to 127.
 
 Tag type 0 is reserved. Tag types 1, 2, and 5 are defined in this
 Internet Draft.  Types 3 and 4 are reserved for work in progress.
 The standard format for all current and future CIPSO tags is shown below:
 
 +----------+----------+--------//--------+
 | TTTTTTTT | LLLLLLLL | IIIIIIIIIIIIIIII |
 +----------+----------+--------//--------+
     TAG       TAG         TAG
     TYPE      LENGTH      INFORMATION
 
     Figure 2:  Standard Tag Format
 
 In the three tag types described in this document, the length and count
 restrictions are based on the current IP limitation of 40 octets for all
 IP options.  If the IP header is later expanded, then the length and count
 restrictions specified in this document may increase to use the full area
 provided for IP options.
 
 
 3.4.1    Tag Type Classes
 
 Tag classes consist of tag types that have common processing requirements
 and support the same security policy.  The three tags defined in this
 Internet Draft belong to the Mandatory Access Control (MAC) Sensitivity
 
 
 
 Internet Draft, Expires 15 Jan 93                                 [PAGE 3]
 
 
 
 CIPSO INTERNET DRAFT                                         16 July, 1992
 
 
 
 class and support the MAC Sensitivity security policy.
 
 
 3.4.2    Tag Type 1
 
 This is referred to as the "bit-mapped" tag type.  Tag type 1 is included
 in the MAC Sensitivity tag type class.  The format of this tag type is as
 follows:
 
 +----------+----------+----------+----------+--------//---------+
 | 00000001 | LLLLLLLL | 00000000 | LLLLLLLL | CCCCCCCCCCCCCCCCC |
 +----------+----------+----------+----------+--------//---------+
 
     TAG       TAG      ALIGNMENT  SENSITIVITY    BIT MAP OF
     TYPE      LENGTH   OCTET      LEVEL          CATEGORIES
 
             Figure 3. Tag Type 1 Format
 
 
 3.4.2.1    Tag Type
 
 This field is 1 octet in length and has a value of 1.
 
 
 3.4.2.2    Tag Length
 
 This field is 1 octet in length.  It is the total length of the tag type
 including the type and length fields.  With the current IP header length
 restriction of 40 bytes the value within this field is between 4 and 34.
 
 
 3.4.2.3    Alignment Octet
 
 This field is 1 octet in length and always has the value of 0.  Its purpose
 is to align the category bitmap field on an even octet boundary.  This will
 speed many implementations including router implementations.
 
 
 3.4.2.4    Sensitivity Level
 
 This field is 1 octet in length.  Its value is from 0 to 255.  The values
 are ordered with 0 being the minimum value and 255 representing the maximum
 value.
 
 
 3.4.2.5    Bit Map of Categories
 
 The length of this field is variable and ranges from 0 to 30 octets.  This
 provides representation of categories 0 to 239.  The ordering of the bits
 is left to right or MSB to LSB.  For example category 0 is represented by
 the most significant bit of the first byte and category 15 is represented
 by the least significant bit of the second byte.  Figure 4 graphically
 shows this ordering.  Bit N is binary 1 if category N is part of the label
 for the datagram, and bit N is binary 0 if category N is not part of the
 label.  Except for the optimized tag 1 format described in the next section,
 
 
 
 Internet Draft, Expires 15 Jan 93                                 [PAGE 4]
 
 
 
 CIPSO INTERNET DRAFT                                         16 July, 1992
 
 
 
 minimal encoding SHOULD be used resulting in no trailing zero octets in the
 category bitmap.
 
         octet 0  octet 1  octet 2  octet 3  octet 4  octet 5
         XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX . . .
 bit     01234567 89111111 11112222 22222233 33333333 44444444
 number             012345 67890123 45678901 23456789 01234567
 
             Figure 4. Ordering of Bits in Tag 1 Bit Map
 
 
 3.4.2.6    Optimized Tag 1 Format
 
 Routers work most efficiently when processing fixed length fields.  To
 support these routers there is an optimized form of tag type 1.  The format
 does not change.  The only change is to the category bitmap which is set to
 a constant length of 10 octets.  Trailing octets required to fill out the 10
 octets are zero filled.  Ten octets, allowing for 80 categories, was chosen
 because it makes the total length of the CIPSO option 20 octets.  If CIPSO
 is the only option then the option will be full word aligned and additional
 filler octets will not be required.
 
 
 3.4.3    Tag Type 2
 
 This is referred to as the "enumerated" tag type.  It is used to describe
 large but sparsely populated sets of categories.  Tag type 2 is in the MAC
 Sensitivity tag type class.  The format of this tag type is as follows:
 
 +----------+----------+----------+----------+-------------//-------------+
 | 00000010 | LLLLLLLL | 00000000 | LLLLLLLL | CCCCCCCCCCCCCCCCCCCCCCCCCC |
 +----------+----------+----------+----------+-------------//-------------+
 
     TAG       TAG      ALIGNMENT  SENSITIVITY         ENUMERATED
     TYPE      LENGTH   OCTET      LEVEL               CATEGORIES
 
                 Figure 5. Tag Type 2 Format
 
 
 3.4.3.1     Tag Type
 
 This field is one octet in length and has a value of 2.
 
 
 3.4.3.2    Tag Length
 
 This field is 1 octet in length. It is the total length of the tag type
 including the type and length fields.  With the current IP header length
 restriction of 40 bytes the value within this field is between 4 and 34.
 
 
 3.4.3.3    Alignment Octet
 
 This field is 1 octet in length and always has the value of 0.  Its purpose
 is to align the category field on an even octet boundary.  This will
 
 
 
 Internet Draft, Expires 15 Jan 93                                 [PAGE 5]
 
 
 
 CIPSO INTERNET DRAFT                                         16 July, 1992
 
 
 
 speed many implementations including router implementations.
 
 
 3.4.3.4    Sensitivity Level
 
 This field is 1 octet in length. Its value is from 0 to 255.  The values
 are ordered with 0 being the minimum value and 255 representing the
 maximum value.
 
 
 3.4.3.5    Enumerated Categories
 
 In this tag, categories are represented by their actual value rather than
 by their position within a bit field.  The length of each category is 2
 octets.  Up to 15 categories may be represented by this tag.  Valid values
 for categories are 0 to 65534.  Category 65535 is not a valid category
 value.  The categories MUST be listed in ascending order within the tag.
 
 
 3.4.4    Tag Type 5
 
 This is referred to as the "range" tag type.  It is used to represent
 labels where all categories in a range, or set of ranges, are included
 in the sensitivity label.  Tag type 5 is in the MAC Sensitivity tag type
 class.  The format of this tag type is as follows:
 
 +----------+----------+----------+----------+------------//-------------+
 | 00000101 | LLLLLLLL | 00000000 | LLLLLLLL |  Top/Bottom | Top/Bottom  |
 +----------+----------+----------+----------+------------//-------------+
 
     TAG       TAG      ALIGNMENT  SENSITIVITY        CATEGORY RANGES
     TYPE      LENGTH   OCTET      LEVEL
 
                      Figure 6. Tag Type 5 Format
 
 
 3.4.4.1     Tag Type
 
 This field is one octet in length and has a value of 5.
 
 
 3.4.4.2    Tag Length
 
 This field is 1 octet in length. It is the total length of the tag type
 including the type and length fields.  With the current IP header length
 restriction of 40 bytes the value within this field is between 4 and 34.
 
 
 3.4.4.3    Alignment Octet
 
 This field is 1 octet in length and always has the value of 0.  Its purpose
 is to align the category range field on an even octet boundary.  This will
 speed many implementations including router implementations.
 
 
 
 
 
 Internet Draft, Expires 15 Jan 93                                 [PAGE 6]
 
 
 
 CIPSO INTERNET DRAFT                                         16 July, 1992
 
 
 
 3.4.4.4    Sensitivity Level
 
 This field is 1 octet in length. Its value is from 0 to 255.  The values
 are ordered with 0 being the minimum value and 255 representing the maximum
 value.
 
 
 3.4.4.5    Category Ranges
 
 A category range is a 4 octet field comprised of the 2 octet index of the
 highest numbered category followed by the 2 octet index of the lowest
 numbered category.  These range endpoints are inclusive within the range of
 categories.  All categories within a range are included in the sensitivity
 label.  This tag may contain a maximum of 7 category pairs.  The bottom
 category endpoint for the last pair in the tag MAY be omitted and SHOULD be
 assumed to be 0.  The ranges MUST be non-overlapping and be listed in
 descending order.  Valid values for categories are 0 to 65534.  Category
 65535 is not a valid category value.
 
 
 3.4.5     Minimum Requirements
 
 A CIPSO implementation MUST be capable of generating at least tag type 1 in
 the non-optimized form.  In addition, a CIPSO implementation MUST be able
 to receive any valid tag type 1 even those using the optimized tag type 1
 format.
 
 
 4.    Configuration Parameters
 
 The configuration parameters defined below are required for all CIPSO hosts,
 gateways, and routers that support multiple sensitivity labels.  A CIPSO
 host is defined to be the origination or destination system for an IP
 datagram.  A CIPSO gateway provides IP routing services between two or more
 IP networks and may be required to perform label translations between
 networks.  A CIPSO gateway may be an enhanced CIPSO host or it may just
 provide gateway services with no end system CIPSO capabilities.  A CIPSO
 router is a dedicated IP router that routes IP datagrams between two or more
 IP networks.
 
 An implementation of CIPSO on a host MUST have the capability to reject a
 datagram for reasons that the information contained can not be adequately
 protected by the receiving host or if acceptance may result in violation of
 the host or network security policy.  In addition, a CIPSO gateway or router
 MUST be able to reject datagrams going to networks that can not provide
 adequate protection or may violate the network's security policy.  To
 provide this capability the following minimal set of configuration
 parameters are required for CIPSO implementations:
 
 HOST_LABEL_MAX - This parameter contains the maximum sensitivity label that
 a CIPSO host is authorized to handle.  All datagrams that have a label
 greater than this maximum MUST be rejected by the CIPSO host.  This
 parameter does not apply to CIPSO gateways or routers.  This parameter need
 not be defined explicitly as it can be implicitly derived from the
 PORT_LABEL_MAX parameters for the associated interfaces.
 
 
 
 Internet Draft, Expires 15 Jan 93                                 [PAGE 7]
 
 
 
 CIPSO INTERNET DRAFT                                         16 July, 1992
 
 
 
 
 HOST_LABEL_MIN - This parameter contains the minimum sensitivity label that
 a CIPSO host is authorized to handle.  All datagrams that have a label less
 than this minimum MUST be rejected by the CIPSO host.  This parameter does
 not apply to CIPSO gateways or routers.  This parameter need not be defined
 explicitly as it can be implicitly derived from the PORT_LABEL_MIN
 parameters for the associated interfaces.
 
 PORT_LABEL_MAX - This parameter contains the maximum sensitivity label for
 all datagrams that may exit a particular network interface port.  All
 outgoing datagrams that have a label greater than this maximum MUST be
 rejected by the CIPSO system.  The label within this parameter MUST be
 less than or equal to the label within the HOST_LABEL_MAX parameter.  This
 parameter does not apply to CIPSO hosts that support only one network port.
 
 PORT_LABEL_MIN - This parameter contains the minimum sensitivity label for
 all datagrams that may exit a particular network interface port.  All
 outgoing datagrams that have a label less than this minimum MUST be
 rejected by the CIPSO system.  The label within this parameter MUST be
 greater than or equal to the label within the HOST_LABEL_MIN parameter.
 This parameter does not apply to CIPSO hosts that support only one network
 port.
 
 PORT_DOI - This parameter is used to assign a DOI identifier value to a
 particular network interface port.  All CIPSO labels within datagrams
 going out this port MUST use the specified DOI identifier.  All CIPSO
 hosts and gateways MUST support either this parameter, the NET_DOI
 parameter, or the HOST_DOI parameter.
 
 NET_DOI - This parameter is used to assign a DOI identifier value to a
 particular IP network address.  All CIPSO labels within datagrams destined
 for the particular IP network MUST use the specified DOI identifier.  All
 CIPSO hosts and gateways MUST support either this parameter, the PORT_DOI
 parameter, or the HOST_DOI parameter.
 
 HOST_DOI - This parameter is used to assign a DOI identifier value to a
 particular IP host address.  All CIPSO labels within datagrams destined for
 the particular IP host will use the specified DOI identifier.  All CIPSO
 hosts and gateways MUST support either this parameter, the PORT_DOI
 parameter, or the NET_DOI parameter.
 
 This list represents the minimal set of configuration parameters required
 to be compliant.  Implementors are encouraged to add to this list to
 provide enhanced functionality and control.  For example, many security
 policies may require both incoming and outgoing datagrams be checked against
 the port and host label ranges.
 
 
 4.1    Port Range Parameters
 
 The labels represented by the PORT_LABEL_MAX and PORT_LABEL_MIN parameters
 MAY be in CIPSO or local format.  Some CIPSO systems, such as routers, may
 want to have the range parameters expressed in CIPSO format so that incoming
 labels do not have to be converted to a local format before being compared
 against the range.  If multiple DOIs are supported by one of these CIPSO
 
 
 
 Internet Draft, Expires 15 Jan 93                                 [PAGE 8]
 
 
 
 CIPSO INTERNET DRAFT                                         16 July, 1992
 
 
 
 systems then multiple port range parameters would be needed, one set for
 each DOI supported on a particular port.
 
 The port range will usually represent the total set of labels that may
 exist on the logical network accessed through the corresponding network
 interface.  It may, however, represent a subset of these labels that are
 allowed to enter the CIPSO system.
 
 
 4.2    Single Label CIPSO Hosts
 
 CIPSO implementations that support only one label are not required to
 support the parameters described above.  These limited implementations are
 only required to support a NET_LABEL parameter.  This parameter contains
 the CIPSO label that may be inserted in datagrams that exit the host.  In
 addition, the host MUST reject any incoming datagram that has a label which
 is not equivalent to the NET_LABEL parameter.
 
 
 5.    Handling Procedures
 
 This section describes the processing requirements for incoming and
 outgoing IP datagrams.  Just providing the correct CIPSO label format
 is not enough.  Assumptions will be made by one system on how a
 receiving system will handle the CIPSO label.  Wrong assumptions may
 lead to non-interoperability or even a security incident.  The
 requirements described below represent the minimal set needed for
 interoperability and that provide users some level of confidence.
 Many other requirements could be added to increase user confidence,
 however at the risk of restricting creativity and limiting vendor
 participation.
 
 
 5.1    Input Procedures
 
 All datagrams received through a network port MUST have a security label
 associated with them, either contained in the datagram or assigned to the
 receiving port.  Without this label the host, gateway, or router will not
 have the information it needs to make security decisions.  This security
 label will be obtained from the CIPSO if the option is present in the
 datagram.  See section 4.1.2 for handling procedures for unlabeled
 datagrams.  This label will be compared against the PORT (if appropriate)
 and HOST configuration parameters defined in section 3.
 
 If any field within the CIPSO option, such as the DOI identifier, is not
 recognized the IP datagram is discarded and an ICMP "parameter problem"
 (type 12) is generated and returned.  The ICMP code field is set to "bad
 parameter" (code 0) and the pointer is set to the start of the CIPSO field
 that is unrecognized.
 
 If the contents of the CIPSO are valid but the security label is
 outside of the configured host or port label range, the datagram is
 discarded and an ICMP "destination unreachable" (type 3) is generated
 and returned.  The code field of the ICMP is set to "communication with
 destination network administratively prohibited" (code 9) or to
 
 
 
 Internet Draft, Expires 15 Jan 93                                 [PAGE 9]
 
 
 
 CIPSO INTERNET DRAFT                                         16 July, 1992
 
 
 
 "communication with destination host administratively prohibited"
 (code 10).  The value of the code field used is dependent upon whether
 the originator of the ICMP message is acting as a CIPSO host or a CIPSO
 gateway.  The recipient of the ICMP message MUST be able to handle either
 value.  The same procedure is performed if a CIPSO can not be added to an
 IP packet because it is too large to fit in the IP options area.
 
 If the error is triggered by receipt of an ICMP message, the message
 is discarded and no response is permitted (consistent with general ICMP
 processing rules).
 
 
 5.1.1    Unrecognized tag types
 
 The default condition for any CIPSO implementation is that an
 unrecognized tag type MUST be treated as a "parameter problem" and
 handled as described in section 4.1.  A CIPSO implementation MAY allow
 the system administrator to identify tag types that may safely be
 ignored.  This capability is an allowable enhancement, not a
 requirement.
 
 
 5.1.2    Unlabeled Packets
 
 A network port may be configured to not require a CIPSO label for all
 incoming  datagrams.  For this configuration a CIPSO label must be
 assigned to that network port and associated with all unlabeled IP
 datagrams.  This capability might be used for single level networks or
 networks that have CIPSO and non-CIPSO hosts and the non-CIPSO hosts
 all operate at the same label.
 
 If a CIPSO option is required and none is found, the datagram is
 discarded and an ICMP "parameter problem" (type 12) is generated and
 returned to the originator of the datagram.  The code field of the ICMP
 is set to "option missing" (code 1) and the ICMP pointer is set to 134
 (the value of the option type for the missing CIPSO option).
 
 
 5.2    Output Procedures
 
 A CIPSO option MUST appear only once in a datagram.  Only one tag type
 from the MAC Sensitivity class MAY be included in a CIPSO option.  Given
 the current set of defined tag types, this means that CIPSO labels at
 first will contain only one tag.
 
 All datagrams leaving a CIPSO system MUST meet the following condition:
 
         PORT_LABEL_MIN <= CIPSO label <= PORT_LABEL_MAX
 
 If this condition is not satisfied the datagram MUST be discarded.
 If the CIPSO system only supports one port, the HOST_LABEL_MIN and the
 HOST_LABEL_MAX parameters MAY be substituted for the PORT parameters in
 the above condition.
 
 The DOI identifier to be used for all outgoing datagrams is configured by
 
 
 
 Internet Draft, Expires 15 Jan 93                                 [PAGE 10]
 
 
 
 CIPSO INTERNET DRAFT                                         16 July, 1992
 
 
 
 the administrator.  If port level DOI identifier assignment is used, then
 the PORT_DOI configuration parameter MUST contain the DOI identifier to
 use.  If network level DOI assignment is used, then the NET_DOI parameter
 MUST contain the DOI identifier to use.  And if host level DOI assignment
 is employed, then the HOST_DOI parameter MUST contain the DOI identifier
 to use.  A CIPSO implementation need only support one level of DOI
 assignment.
 
 
 5.3    DOI Processing Requirements
 
 A CIPSO implementation MUST support at least one DOI and SHOULD support
 multiple DOIs.  System and network administrators are cautioned to
 ensure that at least one DOI is common within an IP network to allow for
 broadcasting of IP datagrams.
 
 CIPSO gateways MUST be capable of translating a CIPSO option from one
 DOI to another when forwarding datagrams between networks.  For
 efficiency purposes this capability is only a desired feature for CIPSO
 routers.
 
 
 5.4    Label of ICMP Messages
 
 The CIPSO label to be used on all outgoing ICMP messages MUST be equivalent
 to the label of the datagram that caused the ICMP message.  If the ICMP was
 generated due to a problem associated with the original CIPSO label then the
 following responses are allowed:
 
   a.  Use the CIPSO label of the original IP datagram
   b.  Drop the original datagram with no return message generated
 
 In most cases these options will have the same effect.  If you can not
 interpret the label or if it is outside the label range of your host or
 interface then an ICMP message with the same label will probably not be
 able to exit the system.
 
 
 6.    Assignment of DOI Identifier Numbers                                   =
 
 Requests for assignment of a DOI identifier number should be addressed to
 the Internet Assigned Numbers Authority (IANA).
 
 
 7.    Acknowledgements
 
 Much of the material in this RFC is based on (and copied from) work
 done by Gary Winiger of Sun Microsystems and published as Commercial
 IP Security Option at the INTEROP 89, Commercial IPSO Workshop.
 
 
 8.    Author's Address
 
 To submit mail for distribution to members of the IETF CIPSO Working
 Group, send mail to: cipso@wdl1.wdl.loral.com.
 
 
 
 Internet Draft, Expires 15 Jan 93                                 [PAGE 11]
 
 
 
 CIPSO INTERNET DRAFT                                         16 July, 1992
 
 
 
 
 To be added to or deleted from this distribution, send mail to:
 cipso-request@wdl1.wdl.loral.com.
 
 
 9.    References
 
 RFC 1038, "Draft Revised IP Security Option", M. St. Johns, IETF, January
 1988.
 
 RFC 1108, "U.S. Department of Defense Security Options
 for the Internet Protocol", Stephen Kent, IAB, 1 March, 1991.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Internet Draft, Expires 15 Jan 93                                 [PAGE 12]
 
 
 

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