PK96706: IT IS NOT POSSIBLE TO CREATE A SERVICE INTEGRATION BUS LINK TO A REMOTE BUS BEHIND A NETWORK ADDRESS TRANSLATION LAYER

Fixes are available

APAR status

Closed as program error.

Error description

With Websphere Application Server v6 and v7, when a Service
Integration Bus(SIB) link is established between two buses,
and the servers are separated by a Network Address
Translation(NAT) layer(using Virtual IP), the connection can
fail with the following exception
CWSIT0059E: It is not possible to establish the inter-bus
connection {0} to messaging engine {1} in bus {2}.
Additionally, if both machines are behind the same Network
Address Translation layer, the link is incorrectly established
using the private IP address rather than the public IP address
configured in the provider endpoint for the bus link
.
KEYWORDS:Service Integration Bus(SIB) Link,NAT,Virtual IP,
CWSIT0059E

Local fix

Problem summary

****************************************************************
* USERS AFFECTED:  Users of the default messaging provider for *
*                  IBM WebSphere Application Server            *
*                  Version 6.1 and Version 7.0                 *
****************************************************************
* PROBLEM DESCRIPTION: It is impossible to create an           *
*                      inter-bus link between buses            *
*                      separated by a Network Address          *
*                      Translation (NAT) layer                 *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
The inter-bus link connection is established in two phases:
1) Bootstrap
   The "Bootstrap endpoints" list of the inter-bus link
   config is used to establish a network link to a server
   in the remote cell (that has the SIB Service enabled).
   This server replies with the network details of the
   server that hosts the messaging engine specified
   in the inter-bus link configuration.
   These network details are based on runtime information
   of the IP address the server is listening on.
2) Complete the connection
   The network details returned by the bootstrap server in the
   remote cell are used to establish a new network connection
   directly to the server that hosts the messaging engine
   specified in the inter-bus link configuration.

This procedure fails when attempting to establish a link
across a Network Address Transaction (NAT) layer, because the
IP address returned during the bootstrap (phase 1) is the
private IP address of the server on the other side of the NAT
layer.

Problem conclusion

The fix for this APAR introduces a new custom property, that
should be specified in the following circumstances:
- An inter-bus link is defined connecting buses defined
in different cells, separated by a Network Address
Translation layer.
- All servers in both cells involved in the inter-bus link
the fix for this APAR applied.
The custom property is enabled by specifying the following line
in a file called "sib.properties", in the "properties"
subdirectory of all profiles in both cells:
sib.trm.meConnBootstrapReuse=true

The custom property allows phase (2) of the connection to
re-use the same network connection that was established in
phase (1) of the connection. However, this re-use only occurs
in the following circumstance:
- The server contacted using the "Bootstrap endpoints"
setting of the inter-bus link hosts the active instance
of the messaging engine specified in the "Remote messaging
engine name" setting of the inter-bus link.
- The network connection used for the bootstrap (as
configured with the "Bootstrap endpoints" setting of the
inter-bus link) is compatible with the "Target inbound
transport chain" setting of the inter-bus link.
For example, BootstrapSecureMessaging and
InboundSecureMessaging would be compatible (assuming no
tunneling or translation of protocols occurs in the network).
As inter-bus links might be established in either direction,
this configuration should be ensured in both directions.

If one of the messaging engines is highly available (a cluster
bus member), then the following special configuration is
required to ensure the above conditions always hold true:
- Define a custom core group policy for the highly
available messaging engine, in the cell that owns the
bus that the messaging engine is in.
The policy should be a "One of N policy", with at least two
match criteria that match the messaging engine.
For example the following two match criteria (where MENAME
is the name of the highly available messaging engine):
type=WSAF_SIB
WSAF_SIB_MESSAGING_ENGINE=MENAME
This core group policy must have the following attributes:
- The 'Failback' option must be checked.
- A 'Preferred servers' list must be specified, containing
at least two servers in a defined order.
- In the other bus (in the other cell) on the inter-bus link
configuration, define exactly the same number of entries
in the "Bootstrap endpoints" list as were specified in the
"Preferred servers" list of the core group policy created
for the remote messaging engine.
Each entry must point to the public IP address, and
appropriate port (such as the SIB_SECURE_ENDPOINT_ADDRESS
port) of the server defined in the "Preferred servers" list.
The entries must be in exactly the same order as the
preferred servers list.
Using this combinations of a custom core group policy, and a
list of provider endpoints, ensures that the bootstrap
connection always connects to the server that hosts the active
instance of the messaging engine.

The fix for this APAR is currently targeted for inclusion in
fix pack 6.1.0.31 and 7.0.0.9.
Refer to the Recommended Updates page for delivery information:
http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980

Temporary fix

Comments

APAR Information

APAR number
PK96706
Reported component name
PLAT MSG COM
Reported component ID
620600101
Reported release
200
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2009-09-21
Closed date
2009-11-26
Last modified date
2009-11-26

APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:

Fix information

Fixed component name
PLAT MSG COM
Fixed component ID
620600101

Applicable component levels

R200 PSY
UP

[{"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SSEQTP","label":"WebSphere Application Server"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"6.1","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
29 December 2021

Tips

PK96706: IT IS NOT POSSIBLE TO CREATE A SERVICE INTEGRATION BUS LINK TO A REMOTE BUS BEHIND A NETWORK ADDRESS TRANSLATION LAYER

Fixes are available

Subscribe

APAR status

Closed as program error.

Error description

Local fix

Problem summary

Problem conclusion

Temporary fix

Comments

APAR Information

APAR number

Reported component name

Reported component ID

Reported release

Status

PE

HIPER

Special Attention

Submitted date

Closed date

Last modified date

APAR is sysrouted FROM one or more of the following:

APAR is sysrouted TO one or more of the following:

Fix information

Fixed component name

Fixed component ID

Applicable component levels

R200 PSY

Document Information

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