[Q] Can't ping to my android JB device from PCs in the same network.

[gabolander]

In my small home network, I have an annoying network issue with my JellyBean (4,1+) Android devices and I couldn't find find a real solution despite my tons of searches in web and forums.

I show you my structure and my current situation:

Netgear DG834GT Modem/Router Wireless
Router IP address: 192.168.0.1
It is configured Gateway, DNS, DHCP (DHCP IP leases over .50) and Upnp.
Wireless is WPA-TKIP secured and only Trusted MacAddress reserved. MacAddress's list is updated with all devices can connect to the router wirelessly.
All managed IPs (both Wired and Wireless) are listed in LAN IP Settings, so they are known by router.

Desktop PC - IP 192.168.0.20 (Static IP)
Laptop PC - IP 192.168.0.65 (Wired)
IP 192.168.0.66 (Wireless)
Laptop and Desktop PC are connected via a Netgear 10/100 4-ports hub, that is lastly connected to one of the 4 ports of the Modem Router.


Galaxy Nexus - IP 192.168.0.75 (Android 4.2.2)

Galaxy Note II - IP 192.168.0.76 (Android 4.1.2)


(Galaxy S II - IP 192.168.0.74 - I don't own it any more, right now)

When I enter in the range of my wireless network with one device, it connects correctly to my wifi and it is able to surf both the web and my local network services with no issues.

PROBLEM: If I enable a server service on one of my JB Android devices (like SSHDroid, FTPDroid, Airdroid, etc) and than I try to connect from my desktop PC (w/ IP 192.168.20) to my Android device, it fails.
If I try to ping android device from my desktop PC (eg. ping 192.168.0.76 to ping Galaxy Note 2), I get this output:

PING 192.168.0.76 (192.168.0.76) 56(84) bytes of data.
From 192.168.0.20 icmp_seq=7 Destination Host Unreachable
From 192.168.0.20 icmp_seq=8 Destination Host Unreachable
From 192.168.0.20 icmp_seq=9 Destination Host Unreachable

Here, I keep the ping command running from PC that reports the error continuosly.
In this while, if I use a terminal emulation app from phone to ping my desktop PC, ping from android device succeeds, and from this moment desktop PC suddenly starts to detect correctly my android device, and command output reports:

.......
64 bytes from galaxynote2 (192.168.0.76): icmp_req=4 ttl=64 time=1748 ms
64 bytes from galaxynote2 (192.168.0.76): icmp_req=5 ttl=64 time=740 ms
...

I ALSO WISH TO PREFACE THAT: until version Android ICS (4.0.4) until I owned Galaxy S2 (or I'm not so sure of that, but certainly until Gingerbread 2.3.6... ), I didn't have this problem. Furtherly, with wireless Router I have in office (Digital Michelangelo wave 54), I don't have this problem too.

Ideas, suggestions, tips?

Tnx in advance for any answers.

Gabo