Re: Only TCP packets towards the Snort host trigger alerts

["Rennhard Marc (rema)" <rema () zhaw ch>]

This solved it, thanks. 

It worked without this option with Snort 2.8.5 / Ubuntu 11.04 - it appears Ubuntu has recently enabled checksum 
offloading.

Cheers,
Marc

On 13. Nov 2012, at 16:08, JJC <cummingsj () gmail com>
 wrote:

> Out of curiosity, are you running with -k none ?
>
>
> On Tue, Nov 13, 2012 at 7:00 AM, Rennhard Marc (rema) <rema () zhaw ch> wrote:
> Dear list members
>
> I'm using Snort for teaching purposes and just updated to Ubuntu 12.04, which implied a Snort update from 2.8.5 to 
> 2.9.2.
>
> The new version shows a different behaviour with respect to TCP packet alerting. Using the rule
>
> alert tcp any any -> any any (msg:"ALL"; sid:9999999;)
>
> and communicating over TCP to a service running on the same host as Snort shows (alerted on) all packets in both 
> directions with Snort 2.8.5.  But with the new Snort version (2.9.2), only packets towards the server generate an 
> alert. With UPD traffic, all packets are alerted on in both directions with both versions.
>
> Has anything changed with respect to alerting on TCP packets between these two versions?
>
> Thanks for any help,
> Marc
>
>
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Prof. Dr. Marc Rennhard
ZHAW Zuercher Hochschule für Angewandte Wissenschaften
InIT Institut fuer angewandte Informationstechnologie
Schwerpunktleiter Information Security
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Monitor your physical, virtual and cloud infrastructure from a single
web console. Get in-depth insight into apps, servers, databases, vmware,
SAP, cloud infrastructure, etc. Download 30-day Free Trial.
Pricing starts from $795 for 25 servers or applications!
http://p.sf.net/sfu/zoho_dev2dev_nov

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