Mosh: Modernizing SSH With IP Roaming, Instant Local Echo

An anonymous reader writes "Launched in 1995, SSH quickly became the king of network login tools, supplanting the old insecure mainstays TELNET and RLOGIN. But 17 years later, a group of MIT hackers have come out with "mosh", which claims to modernize the most annoying parts of SSH. Mosh keeps its connection alive when clients roam among WiFi networks or switch to 3G, and gives instant feedback on typing (and deleting). No more annoying network lag on typing, the MIT boffins say, citing Bufferbloat, which has been increasing latencies." The folks involved have a pre-press research paper with the gritty details (to be presented at USENIX later this year). Mosh itself is not particularly exciting; the new State Synchronization Protocol it is based upon might be: "This is accomplished using a new protocol called the State Synchronization Protocol, for which Mosh is the first application. SSP runs over UDP, synchronizing the state of any object from one host to another. Datagrams are encrypted and authenticated using AES-128 in OCB mode. While SSP takes care of the networking protocol, it is the implementation of the object being synchronized that defines the ultimate semantics of the protocol."

Re:Pass on the local echo please!

[Anonymous Coward]

From their website:

Disable instant echo

$ mosh --predict=never niennunb

The -n switch is a synonym. By contrast, passing --predict=always or -a will enable instant local echo even on low-delay links.

Sounds like it tries to be smart about this, but not so smart as to not allow a human to force things the way he wants them.

Re:Pass on the local echo please!

[Anonymous Coward]

According to their website, locally echoed but not yet synced input is visually distinct from synced content, so you'll always know what has been sent and what hasn't.

Re:Pass on the local echo please!

[Anonymous Coward]

I've been using it for a few days now, and I find the local echo to be quite a useful feature. Many of the machines I remotely use are on different continents, and waiting for my keypress to make a round trip can be frustrating at times.

Mosh also makes it clear which characters have been successfully transmitted by underlining those that are still finding their way through the tubes... i've never been unsure what has or has not been received.

After a few days of using mosh, I don't see myself going back to plain old ssh anytime soon.

Re:OCB Mode is Toxic.

[Anonymous Coward]

according to Wikipedia: [wikipedia.org]

Two U.S. patents have been issued for OCB mode. [1] However, a special exemption has been granted so that OCB mode can be used in software licensed under the GNU General Public License without cost, as well as for any non-commercial, non-governmental application. Since the authors have only applied for patent protection in the U.S., the algorithm is free to use in software not developed and not sold inside the U.S. [2].

Re:OCB Mode is Toxic.

[mikechant]

The patents are freely licensed for any GPL software; see link for details.
http://www.cs.ucdavis.edu/~rogaway/ocb/offer.htm [ucdavis.edu]

Mosh appears to be GPL:
https://github.com/keithw/mosh/blob/master/COPYING [github.com]