[eureka]

BitTorrent put Sync in pre-Alpha Sync in public access. It has Linux ARM client that works on Kindle (as tested on Kindle Touch).

Looking ahead, it could turn into niche solution for syncing Kindle and main computer. Maybe not for all people, but for some.

I've achieved successful syncronization between my computer and Kindle Touch 5.3.2 with Sync v1.0.75. Fact of file creating/deleting is propagated in 5-20 seconds. Here are used configuration files:

• Kindle:
  Spoiler:

  {
    "device_name": "Kindle",
    "listening_port" : 12321,
    "check_for_updates" : false,
    "use_upnp" : false,
    "download_limit" : 0,
    "upload_limit" : 0,
    "shared_folders" :
    [
      {
        "secret" : "X",
        "dir" : "/mnt/us/documents/bridge",
        "use_relay_server" : true,
        "use_dht" : true,
        "search_lan" : false,
        "use_sync_trash" : false
      }
    ]
  }

• computer:
  Spoiler:

  {
    "device_name": "Host",
    "listening_port" : 12322,
    "check_for_updates" : false,
    "use_upnp" : false,
    "download_limit" : 0,
    "upload_limit" : 0,
    "shared_folders" :
    [
      {
        "secret" : "X",
        "dir" : "/home/user/kindle",
        "use_relay_server" : true,
        "use_dht" : true,
        "search_lan" : false,
        "use_sync_trash" : false
      }
    ]
  }

Sync has much more configurable configuration settings (for example, web interface credentials), you can look at them with option

--dump-sample-config

Other command-line options could be viewed with Sync --help .

Sync puts its settings and log in .sync folder along the executable, but it could be changed in configuration file.

Sync can "stuck" on Kindle at the first start just after launch because of low available entropy. You can add available entropy by typing anything on Kindle [virtual] keyboard or by constant swiping over the touchscreen. But anyway, after 3-4 minutes Sync will "continue to work" even without producing the entropy. It needs 640 bits of entropy at first start and if it will be provided with them it will not "stuck". Number of available entropy bits could be displayed with:

cat /proc/sys/kernel/random/entropy_avail

To access Sync web interface (if it's not disabled) you can forward its port with SSH:

ssh -L8889:localhost:8888 root@192.168.15.244

Then access web-interface on localhost:8889 on main computer.

Nothing should be changed in iptables chains. By default, Kindle Touch has policy ACCEPT for OUTPUT chain and rules for ACCEPT tcp with state RELATE/ESTABLISHED and ACCEPT udp with state ESTABLISHED in INPUT chain. It's sufficient for Sync.