strange data traffic

[danielgil () softhome net]

Hi 

Iam using MRTG to monitor the internet traffic in my server, during day time 
the traffic is very intense and by night the traffic slow down 
significantly. This behavior repeat day after day.
But a few days ago the traffic did not slow down as I expected and the MRTG 
show a very intense traffic activity during night-time. 

My question is: 

Can I say that this is hacker activity (perhaps downloading files)?.
Could it be a robot (the ones that index html pages)?. 

My logs doesn't give good hints about this. 


by the way, there is no large files (available to simple users) to download 
in the server. 

any clue ?. 

Thanks in advance

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