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Сегодня ночью обнаружилось, что один из апстрим каналов начал играть в «ванька-встанька».

BGP сессия падала, поднималась, снова падала, снова поднималась и так до бесконечности.

В логах BGP читалось:

Sep  9 00:26:59.219845 RPD_BGP_NEIGHBOR_STATE_CHANGED: BGP peer XX.XX.XX.141 (External AS XXXX) changed state from Established to Idle (event RecvUpdate)
Sep  9 00:27:03.460183 bgp_read_v4_update:8189: NOTIFICATION sent to XX.XX.XX.141 (External AS XXXX): code 3 (Update Message Error) subcode 11 (AS path attribute problem)
Sep  9 00:27:39.219859 RPD_BGP_NEIGHBOR_STATE_CHANGED: BGP peer XX.XX.XX.141 (External AS XXXX) changed state from OpenConfirm to Established (event RecvKeepAlive)

В messages:

Sep  9 00:27:33  rpd[1153]: XX.XX.XX.141 (External AS XXXX) Received BAD update for family inet-unicast(1), prefix 212.118.142.0/24

Полез разбираться, читаем:
BGP Notification Message Error Codes and Error Subcodes

Table 142: BGP Notification Message Error Codes  

Error
Code
Value
Code Name Description
1 Message Header
Error
A problem was detected either
with the contents or length of the BGP header. The Error Subcode
provides more details on the nature of the problem.
2 Open
Message Error
A problem was
found in the body of an Open message. The Error Subtype field
describes the problem in more detail. Note that authentication failures
or inability to agree on a parameter such as hold time are included
here.
3 Update Message
Error
A problem was found in the body
of an Update message. Again, the Error Subtype provides
more information. Many of the problems that fall under this code are
related to issues detected in the routing data or path attributes sent
in the Update message, so these messages provide feedback about
such problems to the device sending the erroneous data.
4 Hold
Timer Expired
A message was
not received before the hold time expired.
See
the description of the Keepalive message for details on this timer
.
5 Finite State
Machine Error
The BGP finite state machine
refers to the mechanism by which the BGP software on a peer moves from
one operating state to another based on events (
see
the TCP finite state machine description for some background on this
concept
). If an event occurs that is unexpected
for the state the peer is currently in, it will generate this error.
6 Cease Used when a
BGP device wants to break the connection to a peer for a reason not
related to any of the error conditions described by the other codes.

Table 143: BGP Notification Message Error Subcodes  

Error
Type
Error
Subcode Value
Subcode
Name
Description
Message
Header Error (Error Code 1)
1 Connection Not
Synchronized
The expected value in the Marker
field was not found, indicating that the connection has become unsynchronized.
See
the description of the Marker field
.
2 Bad
Message Length
The message
was less than 19 bytes, greater than 4096 bytes, or not consistent with
what was expected for the message type.
3 Bad Message
Type
The Type field of the
message contains an invalid value.
Open
Message Error (Error Code 2)
1 Unsupported
Version Number
The device
does not “speak” the version number its peer is trying to
use.
2 Bad Peer AS The router doesn’t recognize
the peer’s autonomous system number or is not willing to communicate
with it.
3 Bad
BGP Identifier
The BGP Identifier
field is invalid.
4 Unsupported
Optional Parameter
The Open message contains
an optional parameter that the recipient of the message doesn’t understand.
5 Authentication
Failure
The data in
the Authentication Information optional parameter could not be
authenticated.
6 Unacceptable
Hold Time
The router refuses to open a
session because the proposed hold time its peer specified in its Open
message is unacceptable.
Update
Message Error (Error Code 3)
1 Malformed
Attribute List
The overall
structure of the message’s
path
attributes
is incorrect, or an attribute
has appeared twice.
2 Unrecognized
Well-Known Attribute
One of the mandatory well-known
attributes was not recognized.
3 Missing
Well-Known Attribute
One of the
mandatory well-known attributes was not specified.
4 Attribute Flags
Error
An attribute has a flag set to
a value that conflicts with the attribute’s type code.
5 Attribute
Length Error
The length
of an attribute is incorrect.
6 Invalid Origin
Attribute
The Origin attribute has
an undefined value.
7 AS
Routing Loop
A routing loop
was detected.
8 Invalid Next_Hop
Attribute
The Next_Hop attribute
is invalid.
9 Optional
Attribute Error
An error was
detected in an optional attribute.
10 Invalid Network
Field
The Network Layer Reachability
Information
field is incorrect.
11 Malformed
AS_Path
The AS_Path
attribute is incorrect.

Такс… приехали…

При помощи своего апстрима удалось выяснить что действительно мне и многим другим другим поднасрал Saudi Telecom и анонсируемый им префикс 212.118.142.0/24.
О чем свидетельствуют мои логи, рассказ апстрима о проблемах и у других его клиентов, а так же:  Saudi Telecom sending route with invalid attributes 212.118.142.0/24:

anyone else getting a route for 212.118.142.0/24 with invalid
attributes? Seems this is (again) causing problems with some (older)
routers/software.

Announcement bits (4): 0-KRT 3-KRT 5-Resolve tree 1
6-Resolve tree 2
AS path: 6453 39386 25019 I Unrecognized Attributes: 39
bytes
AS path: Attr flags e0 code 80: 00 00 fd 88 40 01 01 02
40 02 04 02 01 5b a0 c0 11 04 02 01 fc da 80 04 04 00 00 00 01 40 05 04
00 00 00 64
Accepted Multipath

-Jonas

Ответ:

Exactly the same here.

Sep 8 20:24:04 BBD-RC02 rpd[1334]: Received BAD update from
94.228.128.57 (External AS 41887), aspath_attr():3472
PA4_TYPE_ATTRSET(128) => 1 times IGNORED, family inet-unicast(1), prefix
212.118.142.0/24

Bye,
Raymond.

Смотрим инфу в RIPE:

% Information related to '212.118.140.0/22AS25019'
route: 212.118.140.0/22
descr: Saudi Arabia backbone and local registry address space / STC
remarks: for any Abuse or Spamming Please send an e-mail to abuse@saudi.net.sa
origin: AS25019
mnt-by: saudinet-stc
source: RIPE # Filtered

% Information related to '212.118.140.0/22AS39891'
route: 212.118.140.0/22
descr: Saudi Arabia backbone and local registry address space / STC
origin: AS39891
mnt-by: saudinet-stc
source: RIPE # Filtered

О как, за двумя ASками данный префикс числится. Красавцы, чего тут сказать.

Отфильтровав этот префикс к чертям собачьим, BGP сессия сразу же перестала падать. Вечером та же участь постигла и другого апстрима.

Т.к. к вечеру я уже реально задолбался, то взял отфильтровал нафиг по as-path обе аски  AS39891 и AS25019. Пусть саудовский телеком идет лесом и уже научится пользоваться BGP фильтрами.

Вот так один «олень» может доставить гемороя многим во всем мире.

З.Ы. Junos:

    JUNOS Base OS Software Suite [9.4R1.8]
    JUNOS Kernel Software Suite [9.4R1.8]

Пролеме точно подвержены Junos`ы версии 9.4 и ниже, update JunOS`а ждет меня и не только меня 🙂



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