TCP port 0 or *?

John T. Myers myersj0 at gmail.com
Mon Aug 18 09:02:07 EDT 2014


Also, in testing those filters ‘fragonly’ does not appear to work.

ra -S 192.168.87.211:1776 - fragonly
ra[25298]: 08:48:25.562475 remote Filter error
And when I run : 

ra -S 192.168.87.211:1776 - ip and frag

I get no output at all so I’m not sure if that primitive is actually filtering partial fragments out or just looking for ‘F’ flgs to filter on.



John



On August 18, 2014 at 8:40:06 AM, John T. Myers (myersj0 at gmail.com) wrote:

Carter,

I’m not seeing any ‘F’ in the flgs field, but I am seeing some ‘g’aps. This collect is just from a VM where there is very little traffic. All of the partial ‘f’ragments are being caused by a MySQL connection (between MySQL Workbench and a DB that rasqlinsert is feeding into). We’re talking < 100 flows per second so I’m wondering why it’s missing the first fragmented packet.


On August 18, 2014 at 8:12:24 AM, Carter Bullard (carter at qosient.com) wrote:

Hey John,
These are partial fragments flows, where argus didn't see the first fragment packet.  The fragments don't have either a TCP or UDP header so there aren't any port numbers to generate the 5-tuple flow record.  Argus tracks fragments, but it needs to see the first one to put them all together.   You should be able to filter them out with "not fragonly" or "not frag".  

So why are you getting so many partial fragments, ie why don't you see the first one ??  Load to high so you're droppi g lots of packets??  Load balancers and your seeing only one link of the balance??  PF_RING ???  Gigamons ??  Do you see 5-tuple flows that have fragments ( 'F' in the flgs field) ?

Carter


On Aug 17, 2014, at 9:20 PM, "John T. Myers" <myersj0 at gmail.com> wrote:

I am trying to use Argus to log non-aggregated/processed flow into MySQL, but rasqlinsert sets the port numbers to 0 (or * when just using ra) whenever the “f” partial fragmentation flag is set. Is there a way to just ignore that through a filter ... because it fills up more database rows than any other flows that are being collected.

This happens with a simple: ra -S someipaddress:port ip 

Thanks!

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