KT3 Wi-Fi issue

Thanks to an old tutorial by knc1, I was able to set up wi-fi access from PC to PW1, PW3 and KT3. Using shared keys, no need for password too.

However, I face a peculiar issue with KT3. I'm unable to access KT3 from my PC(netbook running Ubuntu 14.04). Any pings to KT3's I.P don't succeed.

As a workaround, I open kterm on KT3 and from there, ping the PC's I.P - which works. After this, I'm able to ping/connect to KT3 from PC.

This reminds me of similar things I used to do on old PCs at my workplace.

I suppose there must a simple (or profound ;)) reason for this behaviour?