Oracle sending traffic with don't fragment flag set?

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Sep 18th, 2009
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Hi Guys,


Do you have any idea if Oracle clients connecting to Oracle DB are sending traffic with don't fragment flag set?


Just to be sure maybe I should override the fragment flag on inbound on devices (which are all Cisco) where Oracle peers are connected?


For sure I will use sniffer to see what it is all about but wanted to ask if anybody had issues with Oracle over WAN/IPSEC networks.


Regards,


Mladen


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Edison Ortiz Fri, 09/18/2009 - 09:32
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Just to be sure maybe I should override the fragment flag on inbound on devices (which are all Cisco) where Oracle peers are connected?


If you have no control over the application, do it at the router.


This link will provide guidance on the syntax for creating the route-map.


http://www.cisco.com/en/US/tech/tk827/tk369/technologies_white_paper09186a00800d6979.shtml


HTH,


__


Edison.

Joseph W. Doherty Fri, 09/18/2009 - 11:45
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Believe don't fragment flag might be set so that client can perform PMTUD and decrease its packet size to conform with available transit MTU. (I.e. to avoid the need to have every packet fragmented.)


If Oracle is running on top of TCP, you could (if supported by the platform) use the MSS adjust interface command to avoid the need to either fragment packets and/or have client need to work PMTUD. (When properly configured, provides optimal performance for TCP.)


[edit]

Lots of details in reference that Edison provided; worth reading.

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