[mosh-users] Using mosh in UDP-constrained networks (e.g. many public guest wifi networks)

[Ronald MacDonald]

On 8 May 2012, at 05:50, Mike Grant wrote:
>  4. Cross your fingers and, on your client, run:
>    mosh --port 53 username at server

There were a couple of projects begun some time ago, specifically to tunnel SSH via UDP. I've used Ozyman[1], for example, successfully in the past. See also nstx[2].

Part of the problem one may find is that it is not typical to find packet sizes on DNS exceeding 512 bytes*. UDP falls back on TCP if packet length of a DNS query exceeds the 512. So, to get around firewalls that stipulate packet lengths less than that, one is required to fragment the data. Unless you _know_, therefore, all the devices between yourself and endpoint, you can't be sure that, without fragmenting to 512 byte chunks, it's going to work out smoothly and in all cases.

* With the proliferation of DNSSEC, I believe packet sizes are routinely passing the 512 byte length. Does anyone here using FWSM, for example, know if a maximum 512 byte length on DNS is still defined as default?

R

[1] http://ebnj.net/sshoverdns/
[2] http://thomer.com/howtos/nstx.html

R MacDonald : http://www.rmacd.com
ronald at rmacd.com : +1-646-361-7751

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