¿Qué prefijos de IPv6 nunca deben enrutarse?

12

Me parece claro que las direcciones Link Local y Unique Local, al menos, deben filtrarse.

  1. ¿Hay algo más que LLA / ULA que deba filtrarse?

  2. Para LLA, ¿es una práctica estándar filtrar por completo el fe80 :: / 10, o simplemente filtrar el fe80 :: / 64?

Craig Constantine
fuente

Respuestas:

12

RFC 6890 sección 2.2.3 describe prefijos de propósito especial para IPv6. El enlace está aquí:

http://tools.ietf.org/html/rfc6890#page-14

Los prefijos a incluir son:

               +----------------------+------------------+
               | Attribute            | Value            |
               +----------------------+------------------+
               | Address Block        | ::1/128          |
               | Name                 | Loopback Address |
               | RFC                  | [RFC4291]        |
               | Allocation Date      | February 2006    |
               | Termination Date     | N/A              |
               | Source               | False            |
               | Destination          | False            |
               | Forwardable          | False            |
               | Global               | False            |
               | Reserved-by-Protocol | True             |
               +----------------------+------------------+

                    Table 17: Loopback Address

             +----------------------+---------------------+
             | Attribute            | Value               |
             +----------------------+---------------------+
             | Address Block        | ::/128              |
             | Name                 | Unspecified Address |
             | RFC                  | [RFC4291]           |
             | Allocation Date      | February 2006       |
             | Termination Date     | N/A                 |
             | Source               | True                |
             | Destination          | False               |
             | Forwardable          | False               |
             | Global               | False               |
             | Reserved-by-Protocol | True                |
             +----------------------+---------------------+

                   Table 18: Unspecified Address

            +----------------------+---------------------+
            | Attribute            | Value               |
            +----------------------+---------------------+
            | Address Block        | 64:ff9b::/96        |
            | Name                 | IPv4-IPv6 Translat. |
            | RFC                  | [RFC6052]           |
            | Allocation Date      | October 2010        |
            | Termination Date     | N/A                 |
            | Source               | True                |
            | Destination          | True                |
            | Forwardable          | True                |
            | Global               | True                |
            | Reserved-by-Protocol | False               |
            +----------------------+---------------------+

              Table 19: IPv4-IPv6 Translation Address

             +----------------------+---------------------+
             | Attribute            | Value               |
             +----------------------+---------------------+
             | Address Block        | ::ffff:0:0/96       |
             | Name                 | IPv4-mapped Address |
             | RFC                  | [RFC4291]           |
             | Allocation Date      | February 2006       |
             | Termination Date     | N/A                 |
             | Source               | False               |
             | Destination          | False               |
             | Forwardable          | False               |
             | Global               | False               |
             | Reserved-by-Protocol | True                |
             +----------------------+---------------------+

                   Table 20: IPv4-Mapped Address

          +----------------------+----------------------------+
          | Attribute            | Value                      |
          +----------------------+----------------------------+
          | Address Block        | 100::/64                   |
          | Name                 | Discard-Only Address Block |
          | RFC                  | [RFC6666]                  |
          | Allocation Date      | June 2012                  |
          | Termination Date     | N/A                        |
          | Source               | True                       |
          | Destination          | True                       |
          | Forwardable          | True                       |
          | Global               | False                      |
          | Reserved-by-Protocol | False                      |
          +----------------------+----------------------------+

                   Table 21: Discard-Only Prefix

          +----------------------+---------------------------+
          | Attribute            | Value                     |
          +----------------------+---------------------------+
          | Address Block        | 2001::/23                 |
          | Name                 | IETF Protocol Assignments |
          | RFC                  | [RFC2928]                 |
          | Allocation Date      | September 2000            |
          | Termination Date     | N/A                       |
          | Source               | False[1]                  |
          | Destination          | False[1]                  |
          | Forwardable          | False[1]                  |
          | Global               | False[1]                  |
          | Reserved-by-Protocol | False                     |
          +----------------------+---------------------------+

         [1] Unless allowed by a more specific allocation.

                +----------------------+----------------+
                | Attribute            | Value          |
                +----------------------+----------------+
                | Address Block        | 2001::/32      |
                | Name                 | TEREDO         |
                | RFC                  | [RFC4380]      |
                | Allocation Date      | January 2006   |
                | Termination Date     | N/A            |
                | Source               | True           |
                | Destination          | True           |
                | Forwardable          | True           |
                | Global               | False          |
                | Reserved-by-Protocol | False          |
                +----------------------+----------------+

                         Table 23: TEREDO

                +----------------------+----------------+
                | Attribute            | Value          |
                +----------------------+----------------+
                | Address Block        | 2001:2::/48    |
                | Name                 | Benchmarking   |
                | RFC                  | [RFC5180]      |
                | Allocation Date      | April 2008     |
                | Termination Date     | N/A            |
                | Source               | True           |
                | Destination          | True           |
                | Forwardable          | True           |
                | Global               | False          |
                | Reserved-by-Protocol | False          |
                +----------------------+----------------+

                      Table 24: Benchmarking

                +----------------------+---------------+
                | Attribute            | Value         |
                +----------------------+---------------+
                | Address Block        | 2001:db8::/32 |
                | Name                 | Documentation |
                | RFC                  | [RFC3849]     |
                | Allocation Date      | July 2004     |
                | Termination Date     | N/A           |
                | Source               | False         |
                | Destination          | False         |
                | Forwardable          | False         |
                | Global               | False         |
                | Reserved-by-Protocol | False         |
                +----------------------+---------------+

                      Table 25: Documentation

                 +----------------------+--------------+
                 | Attribute            | Value        |
                 +----------------------+--------------+
                 | Address Block        | 2001:10::/28 |
                 | Name                 | ORCHID       |
                 | RFC                  | [RFC4843]    |
                 | Allocation Date      | March 2007   |
                 | Termination Date     | March 2014   |
                 | Source               | False        |
                 | Destination          | False        |
                 | Forwardable          | False        |
                 | Global               | False        |
                 | Reserved-by-Protocol | False        |
                 +----------------------+--------------+

                         Table 26: ORCHID

                +----------------------+---------------+
                | Attribute            | Value         |
                +----------------------+---------------+
                | Address Block        | 2002::/16 [2] |
                | Name                 | 6to4          |
                | RFC                  | [RFC3056]     |
                | Allocation Date      | February 2001 |
                | Termination Date     | N/A           |
                | Source               | True          |
                | Destination          | True          |
                | Forwardable          | True          |
                | Global               | N/A [2]       |
                | Reserved-by-Protocol | False         |
                +----------------------+---------------+

                  [2] See [RFC3056] for details.

                          Table 27: 6to4

                 +----------------------+--------------+
                 | Attribute            | Value        |
                 +----------------------+--------------+
                 | Address Block        | fc00::/7     |
                 | Name                 | Unique-Local |
                 | RFC                  | [RFC4193]    |
                 | Allocation Date      | October 2005 |
                 | Termination Date     | N/A          |
                 | Source               | True         |
                 | Destination          | True         |
                 | Forwardable          | True         |
                 | Global               | False        |
                 | Reserved-by-Protocol | False        |
                 +----------------------+--------------+

                      Table 28: Unique-Local

            +----------------------+-----------------------+
            | Attribute            | Value                 |
            +----------------------+-----------------------+
            | Address Block        | fe80::/10             |
            | Name                 | Linked-Scoped Unicast |
            | RFC                  | [RFC4291]             |
            | Allocation Date      | February 2006         |
            | Termination Date     | N/A                   |
            | Source               | True                  |
            | Destination          | True                  |
            | Forwardable          | False                 |
            | Global               | False                 |
            | Reserved-by-Protocol | True                  |
            +----------------------+-----------------------+

                      Table 29: Linked-Scoped Unicast

Esto debería ser suficiente. También existe la opción de filtrar los bogons, pero eso se siente un poco exagerado a menos que configure el emparejamiento con Team Cymru o algo así.

Daniel Dib
fuente
No estoy de acuerdo con que todas las direcciones de propósito especial "nunca deben ser enrutadas" o que deberían "al menos ser filtradas". Por ejemplo, hay algunos de los que están marcados como "Reenviables" y "Global", en particular 64: ff9b :: / 96 para NAT64.
zevlag
Obviamente, si está utilizando alguno de estos prefijos, no debe filtrarlos. Tal vez esté utilizando Teredo, etc., pero la posición predeterminada debería ser filtrarlos a menos que esté ejecutando NAT o un túnel.
Daniel Dib
2
¿Por qué quieres filtrar 2002 :: / 16? Eso evitaría que cualquiera que esté usando 6to4 como mecanismo de transición se comunique con usted.
Paul Gear
6

Hay tres opciones a las que puedes ir.

El primero, y el más preciso, es configurar el emparejamiento con el Equipo Cymru, como explica SimonJGreen. Tiene la ventaja de tener la lista más precisa, la desventaja de mantener el emparejamiento, las declaraciones de política / mapas de ruta, etc.

La segunda ruta sería negar los prefijos que "nunca debería ver en la naturaleza", como el prefijo local de enlace, el antiguo prefijo 6Bone 3FFE :: / 16, etc. y combinarlo con los prefijos que debería ver. Vea a continuación un ejemplo. La ventaja es que esta es la configuración más fácil, la desventaja es que no es tan precisa como la primera opción.

La tercera ruta, que nunca debe implementar, es tomar la lista actual de bogones de ipv6, según lo publicado por Team Cymru, y pegarla como filtros estáticos en su configuración. Esto es lo que mucha gente hizo con ipv4 hace unos años, y lleva a mucho sufrimiento hoy ... No esta esta opción. Nunca.

Como ejemplo, aquí hay una lista decente de prefijos ipv6 para permitir y prefijos para negar:

ipv6 prefix-list in-filter-v6 seq 5 deny 3ffe::/16 le 128 
ipv6 prefix-list in-filter-v6 seq 10 deny 2001:db8::/32 le 128 
ipv6 prefix-list in-filter-v6 seq 15 permit 2001::/32 
ipv6 prefix-list in-filter-v6 seq 20 deny 2001::/32 le 128 
ipv6 prefix-list in-filter-v6 seq 25 permit 2002::/16 
ipv6 prefix-list in-filter-v6 seq 30 deny 2002::/16 le 128 
ipv6 prefix-list in-filter-v6 seq 35 deny ::/8 le 128 
ipv6 prefix-list in-filter-v6 seq 40 deny fe00::/9 le 128 
ipv6 prefix-list in-filter-v6 seq 45 deny ff00::/8 le 128 
ipv6 prefix-list in-filter-v6 seq 50 permit 2000::/3 le 48 
ipv6 prefix-list in-filter-v6 seq 55 deny ::/0 le 128 
Frank Louwers
fuente
4

Vea la lista de IPv6 Fullbogons en http://www.team-cymru.org/Services/Bogons/http.html

Esto también está disponible a través de DNS , RADB , RIPE o BGP si desea realizar un filtrado automático.

Aquí hay un ejemplo de filtrado automático en Cisco:

router bgp <your asn>
 ! Session 1
 neighbor A.B.C.D remote-as 65332
 neighbor A.B.C.D description <your description>
 neighbor A.B.C.D ebgp-multihop 255
 neighbor A.B.C.D password <your password>
 ! Session 2
 neighbor E.F.G.H remote-as 65332
 neighbor E.F.G.H description <your description>
 neighbor E.F.G.H ebgp-multihop 255
 neighbor E.F.G.H password <your password>
!
 address-family ipv4
  ! Session 1
  neighbor A.B.C.D activate
  neighbor A.B.C.D soft-reconfiguration inbound
  neighbor A.B.C.D prefix-list cymru-out-v4 out
  neighbor A.B.C.D route-map CYMRUBOGONS-V4 in
  ! Session 2
  neighbor E.F.G.H activate
  neighbor E.F.G.H soft-reconfiguration inbound
  neighbor E.F.G.H prefix-list cymru-out-v4 out
  neighbor E.F.G.H route-map CYMRUBOGONS-V4 in
!
 address-family ipv6
  ! Session 1
  neighbor A.B.C.D activate
  neighbor A.B.C.D soft-reconfiguration inbound
  neighbor A.B.C.D prefix-list cymru-out-v6 out
  neighbor A.B.C.D route-map CYMRUBOGONS-V6 in
  ! Session 2
  neighbor E.F.G.H activate
  neighbor E.F.G.H soft-reconfiguration inbound
  neighbor E.F.G.H prefix-list cymru-out-v6 out
  neighbor E.F.G.H route-map CYMRUBOGONS-V6 in
!
! Depending on IOS version, you may need to configure your router
! for new-style community syntax.
ip bgp-community new-format
!
ip community-list 100 permit 65332:888
!
ip route 192.0.2.1 255.255.255.255 Null0
!
ip prefix-list cymru-out-v4 seq 5 deny 0.0.0.0/0 le 32
!
ipv6 route 2001:DB8:0:DEAD:BEEF::1/128 Null0
!
ipv6 prefix-list cymru-out-v6 seq 5 deny ::/0 le 128
!
route-map CYMRUBOGONS-V6 permit 10
description IPv6 Filter bogons learned from cymru.com bogon route-servers
match community 100
set ipv6 next-hop 2001:DB8:0:DEAD:BEEF::1
!
route-map CYMRUBOGONS-V4 permit 10
description IPv4 Filter bogons learned from cymru.com bogon route-servers
match community 100
set ip next-hop 192.0.2.1

Y aquí hay uno para JunOS:

/*
* Define BGP peer group
*/
delete protocols bgp group cymru-bogons
set protocols bgp group cymru-bogons type external
set protocols bgp group cymru-bogons description "cymru fullbogon bgp feed (ipv4 + 6)"
set protocols bgp group cymru-bogons multihop ttl 255
set protocols bgp group cymru-bogons import cymru-bogons-in
/*
* Define MD5 password in quotes
*/
set protocols bgp group cymru-bogons authentication-key "<YOUR PASSWORD>"
set protocols bgp group cymru-bogons export deny-all
set protocols bgp group cymru-bogons peer-as 65332
/*
* Replace values below as appropriate
*/
set protocols bgp group cymru-bogons neighbor A.B.C.D local-address <YOUR IP>
set protocols bgp group cymru-bogons neighbor A.B.C.D family inet unicast
set protocols bgp group cymru-bogons neighbor A.B.C.D family inet6 unicast
set protocols bgp group cymru-bogons neighbor E.F.G.H local-address <YOUR IP>
set protocols bgp group cymru-bogons neighbor E.F.G.H family inet unicast
set protocols bgp group cymru-bogons neighbor E.F.G.H family inet6 unicast
/*
* Define CYMRU import policy
*/
delete policy-options policy-statement cymru-bogons-in
set policy-options policy-statement cymru-bogons-in term 1 from family inet
set policy-options policy-statement cymru-bogons-in term 1 from community comm-cymru-bogon
set policy-options policy-statement cymru-bogons-in term 1 then community add no-export
set policy-options policy-statement cymru-bogons-in term 1 then next-hop discard
set policy-options policy-statement cymru-bogons-in term 1 then accept
set policy-options policy-statement cymru-bogons-in term 2 from family inet6
set policy-options policy-statement cymru-bogons-in term 2 from community comm-cymru-bogon
set policy-options policy-statement cymru-bogons-in term 2 then community add no-export
set policy-options policy-statement cymru-bogons-in term 2 then next-hop discard
set policy-options policy-statement cymru-bogons-in term 2 then accept
set policy-options policy-statement cymru-bogons-in then reject
/*
* Define deny-all export policy
*/
delete policy-options policy-statement deny-all
set policy-options policy-statement deny-all then reject
/*
* Define CYMRU Bogon community
*/
delete policy-options community comm-cymru-bogon
set policy-options community comm-cymru-bogon members no-export
set policy-options community comm-cymru-bogon members 65332:888
/*
* Define internal no-export community
*/
delete policy-options community comm-no-export
set policy-options community comm-no-export members no-export
SimonJGreen
fuente