Windows 7.92 XML Evolution - problems with logging in

[qndel]

I'm running my server on a virtual machine, everything works fine, I've forwarded the ports etc.
There is just one problem - sometimes I can't log in for random periods of time.
I've been reading some stuff about open tibia servers and I've found a mention of 'game port attack'.
Is it possibe that somebody is attacking my server's port and therefore blocking the ability to log in?
If yes, how can I protect myself against it?
Or what else might cause that problems?
Thanks in advance for the help

 

[qndel]

#bump

 

[qndel]

#bump

 

[qndel]

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[qndel]

#derp

 

[Shyzoul]

dude no one here knows whats going on in your network, first of all bring something that we can help you, microsoft has a software to see all in/out datas, search and use it to make a log so we can start from somewhere, is an attack or server problem.

 

[qndel]

I say it's an attack, because a guy has told me 'look, I will make it so people can't log on your server' and he did it few minutes later - I'm just wondering what he did and how to protect against it