Cannot connect (MacOSX client, Debian server)

[ErikDeBruijn]

Hi,

I just wanted to say that this is a long awaited feature... a client that is robust to roaming around, as many of us do.

I compiled the recent version from git for the server (a Debian Squeeze/sid machine) and am using the MacPorts version of mosh.

When running It I get the following error:

mosh root@server4

mosh requires a UTF-8 locale.
Connection to server4 closed.
/opt/local/bin/mosh: Did not find mosh server startup message.

I fiddled around with my client's /etc/ssh_config but this didn't help. What can I do to resolve this and start using mosh?

[keithw]

Hello. Please run "locale" and then "ssh root@server4 locale". Do both show a UTF-8 LC_CTYPE?

If the latter doesn't, you have some options. Make sure that SendEnv LANG LC_* is on your local /etc/ssh_config (this is the default configuration on OS X) and AcceptEnv LANG LC_* is in the server's /etc/ssh/sshd_config (this has been the default on Debian for the last few releases, but not forever).

If you can't arrange that, you can try running:

mosh root@server4 --server="LANG=$LANG mosh-server"

That will explicitly pass the LANG environment variable.

[ErikDeBruijn]

Thanks for your response. I still can't get it to work, though. Tried setting LANG to various values, to no avail.

I had the SendEnv and AcceptEnv in place on client and server (respectively), reloaded the sshd config. But I still get the same response.
Just a thought: If it's not going to work without UTF-8, why allow the user to configure this and allow for more room for error? It would be nice if figuring out what locales are would not be required to use this, just like you don't need to understand it before you can use ordinary SSH.

Running locale on the client gives me:

locale

LANG=
LC_COLLATE="C"
LC_CTYPE="C"
LC_MESSAGES="C"
LC_MONETARY="C"
LC_NUMERIC="C"
LC_TIME="C"
LC_ALL=

[keithw]

Unfortunately, it's not exactly an install-time concern -- the choice of locale is the user's, in setting their environment variables. I agree it's not a concern with SSH, but SSH also doesn't correctly handle UTF-8 (you will get garbage in your buffers if you try to use delete in cooked mode), so that's not really much consolation for us!

On your Mac, can you set LANG=en_US.UTF-8 (or whatever your choice of language is, .UTF-8) and then run "locale"? If that doesn't work, we may need to figure out how to build the right locales for you...

[jamesamcl]

Same problem here (Arch Linux client, FreeBSD server).

[james@james-desktop mosh]$ locale
LANG=
LC_CTYPE="POSIX"
LC_NUMERIC="POSIX"
LC_TIME="POSIX"
LC_COLLATE="POSIX"
LC_MONETARY="POSIX"
LC_MESSAGES="POSIX"
LC_PAPER="POSIX"
LC_NAME="POSIX"
LC_ADDRESS="POSIX"
LC_TELEPHONE="POSIX"
LC_MEASUREMENT="POSIX"
LC_IDENTIFICATION="POSIX"
LC_ALL=

[james@james-desktop mosh]$ ssh root@95.211.73.134 locale
LANG=
LC_CTYPE="C"
LC_COLLATE="C"
LC_TIME="C"
LC_NUMERIC="C"
LC_MONETARY="C"
LC_MESSAGES="C"
LC_ALL=

[james@james-desktop mosh]$ mosh root@95.211.73.134
bash: mosh-server: command not found
Connection to 95.211.73.134 closed.
/usr/local/bin/mosh: Did not find mosh server startup message.

[keithw]

Hi udp,

You'll need to be using a UTF-8 locale to use Mosh. Can you set LANG=en_US.UTF-8 on your local machine? (You may have to build that locale with localegen...)

[BinaryPaean]

I'm also getting the same error, but with UTF-8 locales (apparently) set.
mosh installed locally via mac ports, installed remotely via apt-get ppa.

result of local locale command:

locale
LANG="en_US.utf-8"
LC_COLLATE="en_US.utf-8"
LC_CTYPE="en_US.utf-8"
LC_MESSAGES="en_US.utf-8"
LC_MONETARY="en_US.utf-8"
LC_NUMERIC="en_US.utf-8"
LC_TIME="en_US.utf-8"
LC_ALL=

remote machine locale:

locale
LANG=en_US.UTF-8
LANGUAGE=
LC_CTYPE=en_US.utf-8
LC_NUMERIC="en_US.UTF-8"
LC_TIME="en_US.UTF-8"
LC_COLLATE="en_US.UTF-8"
LC_MONETARY="en_US.UTF-8"
LC_MESSAGES="en_US.UTF-8"
LC_PAPER="en_US.UTF-8"
LC_NAME="en_US.UTF-8"
LC_ADDRESS="en_US.UTF-8"
LC_TELEPHONE="en_US.UTF-8"
LC_MEASUREMENT="en_US.UTF-8"
LC_IDENTIFICATION="en_US.UTF-8"
LC_ALL=

adding the --server="LANG=$LANG mosh-server" flag worked. Is there an expectation that the locale string be quoted?

[keithw]

Quotes shouldn't matter, but we do have trouble right now with lowercase "utf-8". (Bug #104). Glad you got it working.

[ErikDeBruijn]

I've also added export LANG=en_US.UTF-8 to ~/.bashrc on the server, to no avail.

LANG="en_US.UTF-8"
LC_COLLATE="en_US.UTF-8"
LC_CTYPE="en_US.UTF-8"
LC_MESSAGES="en_US.UTF-8"
LC_MONETARY="en_US.UTF-8"
LC_NUMERIC="en_US.UTF-8"
LC_TIME="en_US.UTF-8"

I also ran locale-gen.

Still, I get the following:

 # mosh root@server4
mosh requires a UTF-8 locale.
Connection to server4 closed.
/opt/local/bin/mosh: Did not find mosh server startup message.

Is the UTF-8 really the reason why it's not working? Or could there be something else. I found no flag to make mosh verbose... If an error message points me in the right direction, usually I don't need to ask any developers. I'm sorry to take up so much of your time.

[srmadden]

I managed to get this to work after seeing issues liked those above. There were a couple of things that confused me. First, on my Mac running Lion (10.7), /etc/ssh_config definitely doesn't have the SendEnv flags set (although the Linux machine I was trying to mosh too did have them set.) Second, when Keith says SendEnv LC_* above, you have to explicitly type out all of the LC_.... variables that need to be sent and received.

To be precise, in /etc/ssh_config on the client (a Mac), I added:

SendEnv LANG LC_CTYPE LC_NUMERIC LC_TIME LC_COLLATE LC_MONETARY LC_MESSAGES
SendEnv LC_PAPER LC_NAME LC_ADDRESS LC_TELEPHONE LC_MEASUREMENT
SendEnv LC_IDENTIFICATION LC_ALL LANGUAGE

And on the server, in /etc/ssh/sshd_config, I made sure I had:

Accept locale-related environment variables

AcceptEnv LANG LC_CTYPE LC_NUMERIC LC_TIME LC_COLLATE LC_MONETARY LC_MESSAGES
AcceptEnv LC_PAPER LC_NAME LC_ADDRESS LC_TELEPHONE LC_MEASUREMENT
AcceptEnv LC_IDENTIFICATION LC_ALL LANGUAGE

[ErikDeBruijn]

Thanks, srmadden, for adding your solution. I also added these to the configuration(s) of client and server. It's still not working. I'm wondering whether there could be other reasons why it's not working. Is there a verbose mode? Is there something else I can test? Can it display the server message that it's getting and can I manually diagnose that?

[keithw]

Thanks Sam. Unfortunately I don't have a great handle on when this became the default -- there may be a difference between new installs and upgrades. I have also seen somebody on OS X 10.6 who did not have the /etc/ssh_config line but was still passing the env vars.

On Debian/Ubuntu (and some [recent?] OS X installations...) the line really is just "SendEnv LANG LC_*" with a literal star, but if you have to type it all out somewhere, hmm. I just don't know. Thanks for tracking this down and glad you got it working eventually. We obviously do not totally understand the landscape here.

[keithw]

Erik: Just to make sure.

(1) When you run plain "locale" at the local command line, do you see "LC_CTYPE="en_US.UTF-8"" but also no error messages complaining about "Cannot set LC_CTYPE..."?

(2) When you run "ssh remotehost locale", ditto? No error messages?

(3) When you run the mosh-client and mosh-server separately as detailed on mosh.mit.edu, does it work properly or not work?

(4) If you do get an error, you may have to run "locale-gen en_US.UTF-8" with the argument, not just by itself.

Thanks for your patience,
Keith

[ErikDeBruijn]

Strange... it still reads the following:

# ssh root@server4 locale
\LANG=
LANGUAGE=
LC_CTYPE="POSIX"
LC_NUMERIC="POSIX"
LC_TIME="POSIX"
LC_COLLATE="POSIX"
LC_MONETARY="POSIX"
LC_MESSAGES="POSIX"
LC_PAPER="POSIX"
LC_NAME="POSIX"
LC_ADDRESS="POSIX"
LC_TELEPHONE="POSIX"
LC_MEASUREMENT="POSIX"
LC_IDENTIFICATION="POSIX"
LC_ALL=

Even though I've set /etc/profile and ~/.bashrc and ~/.bash_profile to export LANG=en_US.UTF-8....

[jaredrichardson]

I also can't connect. I'm coming from Lion (on 2 different installs) to a Linux Mint box. locale returns the correct settings and both client and server, and I tried srmadden's solution. I'd love to use mosh, but I can't even connect w/the explicit mosh-client and mosh-server settings.

I wish there was some level of logging or debug messaging we could see.