FreeNX 4.0: connect to Ubuntu FreeNX server from Android devices with FreeNX client

There is a FreeNX client for Android devices.

You can download it as below.

https://www.nomachine.com/download

Android ( Nexus 7, Kitkat ) ---- Ubuntu 13.10

FreeNX client                           FreeNX server

How to set up FreeNX server on Ubuntu, please see the below.

http://lost-and-found-narihiro.blogspot.jp/2013/11/nomachine-freenx-40-on-ubuntu-1310.html

The following is when connecting to the Ubuntu box from the Nexus 7.

Capture data of Android 4.4.2 Nexus 7 ( DNS queries and TCP SYN packets )

just for my memo.

Here are packet dumps of my Nexus 7 tablet connected to Wifi.

[ DNS queries ]

does not add EDNS0 option.

Android 4.4.2 ( Nexus 7 )

Domain Name System (query)    Transaction ID: 0x4602    Flags: 0x0100 Standard query        0... .... .... .... = Response: Message is a query        .000 0... .... .... = Opcode: Standard query (0)        .... ..0. .... .... = Truncated: Message is not truncated        .... ...1 .... .... = Recursion desired: Do query recursively        .... .... .0.. .... = Z: reserved (0)        .... .... ...0 .... = Non-authenticated data: Unacceptable    Questions: 1    Answer RRs: 0    Authority RRs: 0    Additional RRs: 0    Queries        www.bing.com: type A, class IN            Name: www.bing.com            Type: A (Host address)            Class: IN (0x0001)

[ TCP SYN packet ]

Android 4.4.2 ( Nexus 7 )

enable window scaling and selective ack.. I didn’t know that.

Options: (20 bytes), Maximum segment size, SACK permitted, Timestamps, No-Operation (NOP), Window scale        Maximum segment size: 1460 bytes            Kind: MSS size (2)            Length: 4            MSS Value: 1460        TCP SACK Permitted Option: True            Kind: SACK Permission (4)            Length: 2        Timestamps: TSval 532510, TSecr 0            Kind: Timestamp (8)            Length: 10            Timestamp value: 532510            Timestamp echo reply: 0        No-Operation (NOP)            Type: 1                0... .... = Copy on fragmentation: No                .00. .... = Class: Control (0)                ...0 0001 = Number: No-Operation (NOP) (1)        Window scale: 6 (multiply by 64)            Kind: Window Scale (3)            Length: 3            Shift count: 6            [Multiplier: 64]

packet capture on Android : tpacket capture

tpacketcapture is packet capture tool for Andoroid , which is free.
https://play.google.com/store/apps/details?id=jp.co.taosoftware.android.packetcapture&hl=en

no need to be root user. nice tool.
tpacketcapture enables you to capture network traffic on Android and then upload pcap file via e-mail , dropbox.

The following is the output of pcap files I got on Nexsus 7 and Optimus G devices.

Seen from the pcap file , scaling factor is 6 ( 2**6 = 64 ) and selective ack is enabled on both devices.

packet file captured on Nexsus 7 ( Android 4.2 )

# tshark -r nexsus7.pcap -n -R '(tcp.flags.syn==1)' | head -1  1   0.000000     x.x.x.x -> z.z.z.z TCP 74 37780 > 443 [SYN] Seq=0 Win=14600 Len=0 MSS=1460 SACK_PERM=1 TSval=5302230 TSecr=0 WS=64

packet file captured on Optimus G. ( Android 4.0 )

# tshark -r optimus_g.pcap -n -R '(tcp.flags.syn==1)' | head -1  1   0.000000     x.x.x.x -> z.z.z.z TCP 74 34680 > 80 [SYN] Seq=0 Win=14600 Len=0 MSS=1460 SACK_PERM=1 TSval=3878335 TSecr=0 WS=64