Openssh on N900
 

Hello everyone,

Hope I am writing on the right forum, if not - my apologies.
I am new to Maemo and have no experience with previous devices, so I can't compare behaviour.

I started to play with new and shiny N900 with noble goal to develop Qt based application. One of steps on the way is to establish ssh to N900. I can't say it does not work completely. It works. Somewhat. I installed the latest openssh, 5.1p1-6 maemo5, and that's what I got.

1. I can not connect at all from Hardy Ubuntu laptop via WiFi. Probably Hardy's problem, read about similar problems on forums.

2. I managed to connect to the same Hardy laptop from N900, not always but sometimes

3. SSH within N900 works fine, from user account to root, the server is running.

4. I sometimes can connect via wires from another laptop running Mepis.

[I]ssh -l root 192.168.0.103
The authenticity of host '192.168.0.103 (192.168.0.103)' can't be established.
RSA key fingerprint is ba:6e:e8:d7:a0:c3:3f:57:75:92:4b:b2:ea:37:6b:85.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.0.103' (RSA) to the list of known hosts.
root@192.168.0.103's password:


BusyBox v1.10.2 (Debian 3:1.10.2.legal-1osso26+0m5) built-in shell (ash)
Enter 'help' for a list of built-in commands.

Nokia-N900-42-7:~#
Nokia-N900-42-7:~#
Nokia-N900-42-7:~# ls
Nokia-N900-42-7:~# lsls
-sh: lsls: not found

Nokia-N900-42-7:~#
Nokia-N900-42-7:~# lsls
-sh: lsls: not found
Nokia-N900-42-7:~# ls
Nokia-N900-42-7:~#
Nokia-N900-42-7:~# Read from remote host 192.168.0.103: Connection timed out
Connection to 192.168.0.103 closed.

N900 responds very sloooowwwly. This is session of about 12 minutes. Other way around i.e. N900 ->laptop was much better, not perfect either but at least respond was within seconds, not minutes.

5. I was pinging the N900 to keep wifi alive, here is the result.


ping 192.168.0.103 -i 5
PING 192.168.0.103 (192.168.0.103): 56 data bytes
64 bytes from 192.168.0.103: icmp_seq=4 ttl=64 time=81.5 ms
64 bytes from 192.168.0.103: icmp_seq=15 ttl=64 time=2049.5 ms
64 bytes from 192.168.0.103: icmp_seq=27 ttl=64 time=2105.5 ms
64 bytes from 192.168.0.103: icmp_seq=51 ttl=64 time=2122.3 ms
64 bytes from 192.168.0.103: icmp_seq=68 ttl=64 time=13.0 ms
64 bytes from 192.168.0.103: icmp_seq=81 ttl=64 time=2042.3 ms
64 bytes from 192.168.0.103: icmp_seq=91 ttl=64 time=2052.8 ms
64 bytes from 192.168.0.103: icmp_seq=111 ttl=64 time=2119.5 ms
64 bytes from 192.168.0.103: icmp_seq=135 ttl=64 time=2036.8 ms
64 bytes from 192.168.0.103: icmp_seq=147 ttl=64 time=2097.8 ms
64 bytes from 192.168.0.103: icmp_seq=159 ttl=64 time=2057.4 ms
64 bytes from 192.168.0.103: icmp_seq=171 ttl=64 time=2116.3 ms
64 bytes from 192.168.0.103: icmp_seq=172 ttl=64 time=81.9 ms
64 bytes from 192.168.0.103: icmp_seq=183 ttl=64 time=2079.0 ms
64 bytes from 192.168.0.103: icmp_seq=207 ttl=64 time=1073.5 ms
64 bytes from 192.168.0.103: icmp_seq=219 ttl=64 time=1129.9 ms
64 bytes from 192.168.0.103: icmp_seq=231 ttl=64 time=1070.1 ms
64 bytes from 192.168.0.103: icmp_seq=255 ttl=64 time=1086.6 ms
64 bytes from 192.168.0.103: icmp_seq=267 ttl=64 time=1047.4 ms
64 bytes from 192.168.0.103: icmp_seq=279 ttl=64 time=1108.5 ms
64 bytes from 192.168.0.103: icmp_seq=291 ttl=64 time=1064.3 ms
64 bytes from 192.168.0.103: icmp_seq=303 ttl=64 time=1116.7 ms
64 bytes from 192.168.0.103: icmp_seq=339 ttl=64 time=1123.2 ms
64 bytes from 192.168.0.103: icmp_seq=351 ttl=64 time=1081.7 ms
64 bytes from 192.168.0.103: icmp_seq=363 ttl=64 time=1123.5 ms
64 bytes from 192.168.0.103: icmp_seq=375 ttl=64 time=1078.3 ms
64 bytes from 192.168.0.103: icmp_seq=387 ttl=64 time=1033.0 ms
64 bytes from 192.168.0.103: icmp_seq=411 ttl=64 time=1042.6 ms
64 bytes from 192.168.0.103: icmp_seq=423 ttl=64 time=42.0 ms
64 bytes from 192.168.0.103: icmp_seq=435 ttl=64 time=101.2 ms
64 bytes from 192.168.0.103: icmp_seq=447 ttl=64 time=61.5 ms
64 bytes from 192.168.0.103: icmp_seq=459 ttl=64 time=117.8 ms
64 bytes from 192.168.0.103: icmp_seq=471 ttl=64 time=77.0 ms
64 bytes from 192.168.0.103: icmp_seq=483 ttl=64 time=35.9 ms
64 bytes from 192.168.0.103: icmp_seq=495 ttl=64 time=95.3 ms
64 bytes from 192.168.0.103: icmp_seq=507 ttl=64 time=55.3 ms
64 bytes from 192.168.0.103: icmp_seq=513 ttl=64 time=54.1 ms
64 bytes from 192.168.0.103: icmp_seq=525 ttl=64 time=2042.5 ms
64 bytes from 192.168.0.103: icmp_seq=526 ttl=64 time=108.8 ms
64 bytes from 192.168.0.103: icmp_seq=543 ttl=64 time=45.4 ms
64 bytes from 192.168.0.103: icmp_seq=555 ttl=64 time=101.9 ms
64 bytes from 192.168.0.103: icmp_seq=567 ttl=64 time=47.9 ms
64 bytes from 192.168.0.103: icmp_seq=579 ttl=64 time=121.6 ms
64 bytes from 192.168.0.103: icmp_seq=615 ttl=64 time=84.5 ms

--- 192.168.0.103 ping statistics ---
633 packets transmitted, 45 packets received, 92% packet loss
round-trip min/avg/max = 13.0/921.4/2122.3 ms


What is your experience with ssh'ing to N900?

Any suggestion will be much appreciated.


Boris.

Re: Openssh on N900
 

Do you have the same packet loss wired? With this kind of packet loss ofcourse you're getting bad network-related performance... probably not only SSH which works shitty.

Re: Openssh on N900
 

I am not sure if this is the right way to be measuring network performance. Firstly, how many hops are there to your device - is there a router in the way? Maybe using some tool like iperf might help though that is a bit complicated to install. tcpdump might help too or going the simplest route with ssh -vv.

In any case, the data here is a little too small to serve as a representative sample.

Re: Openssh on N900
 

WiFi power-saving causes problems with SSH.
Making connections from computer to tablet often fails because the tablet doesn't answer. Doing some network action on the tablet activates WiFi again and you'll get a response.

For SSH and SCP I open a X-Terminal on the N900, gain root, and start pinging my router. Then I can easily access the tablet from my computer without having to turn off power-saving. When I'm done, I stop the pinging.

Re: Openssh on N900
 

The N900 must send the pings to keep the WiFi alive, not the other way round.

Re: Openssh on N900
 

I'm not entirely convinced by that: to keep alive the WiFi, having traffic on the interface should be enough. By pinging from an external source the device, you will generate traffic (both inbound and outbound), thus keeping alive the WiFi...but maybe it's different on the N900?

Re: Openssh on N900
 

The connection between Mepis laptop and router is wired. The router is within meter and a half from both devices :)
What bothers me is pretty constant time between responses on Ping, around 2 sec initially, and around 1 sec after. The spikes happened when I activated N900.

Re: Openssh on N900
 

That's what I thought while pinging N900 from outside. It did not work. Pinging other way around keeps wifi active, with no packet loss. The time is between 10-40 msec, as opposite to 2 sec. This is probably specific to N900.

Re: Openssh on N900
 

Thanks pycage.
It works somewhat better now. Still it is very slow response to commands entered, seconds, sometimes tens of seconds. Do you see the same ?

Re: Openssh on N900
 

If you run Mepis laptop on LAN and other laptop on WLAN performance is acceptable? At this point I'd start to do some packet capturing...

Re: Openssh on N900
 

The performance is really good when I ssh from N900 to another computer. WLAN works okay with number of other devices, laptops, iPhone, N95.

Re: Openssh on N900
 

Hang it on charger, put PSM off, and ping the thing. It should increase. Else, run tcpdump on the N900.

Re: Openssh on N900
 

No, I don't see this. You could try switching power-saving from highest level to medium on the N900 if you haven't already done so.

Re: Openssh on N900
 

I strongly suggest getting a Linksys / Cisco WRT54GL router and flashing custom firmware. I have had no problems with that router, while I have had many problems with other routers.

Re: Openssh on N900
 

The router does not explain that ssh from N900 out works well. scp initiated from N900 ( copying from a laptop to N900 ) produced 963.7KB/s.

Re: Openssh on N900
 

to finish the story, turning PSM off solves the problems. Thanks everyone for the help.

Re: Openssh on N900
 

PSM? Power saving? That's not a solution, that's a workaround or a hack. You'll notice your battery draining much more quickly with power saving disabled.

A good router is the actual solution.

Re: Openssh on N900
 

And how did you turn it off?

Re: Openssh on N900
 

Settings->Internet Connections->Connections->Edit connection->Next ( several Next - until Advanced appears ) -> Advanced->Other->Power saving.
There are three options, Maximum, Intermediate and Off. In my case ssh works with Off selected, does not work with Maximum and somewhat works with Intermediate.

Re: Openssh on N900
 

Ouch, with PSM off you can expect your uptime to drop dramatically. For me it's a 48 hours down to 2.5 hours change (until the device starts to beep for 'low battery warning').

Re: Openssh on N900
 

How disappointing... Either have to turn Powersaving off, or you have to buy a specific router :(

Re: Openssh on N900
 

Well, it's more about avoiding specific routers.. the wast majority should work ok.

Re: Openssh on N900
 

At the end it is not that bad. I don't need ssh to the device all the time, and when I do need - it is in the home/office environment. Just plugging it in and don't forget to switch back PSM when everything is done...
Perfect recipe to get a new router after couple of days of doing this though ;-)

Re: Openssh on N900
 

I don't believe that it's router problem. My N800 works perfectly with incoming SSH on the same router(Netgear WGR614 v7). It's probably something with N900's implementation of PSM.

Right now the only solution for non-Linksys people seems to be turning off PSM temporarily.

Re: Openssh on N900
 

I am using a AVM FritzBox! router and the problem is the same:
no reaction or reactions after 15 seconds and more. Sometimes the connection fails completely.

FritzBox! routers are very popular in Germany so I think this problem will have a lot of people here. I also have no problems with my N800 in the same network...

Should there be filled a bug report in the section:

Maemo Official Platform --> Connectivity --> WiFi?

Or should the be a bug report for openssh. If yes, where is the bug reporting site for maemo openssh?

Re: Openssh on N900
 

That's the right place IMHO, but comment/vote on the existing one instead.

Probably its garage page, but it really should be listed in the package according to http://wiki.maemo.org/Extras-testing...rting_database.

Re: Openssh on N900
 

This bug has been fixed in Firmware version 1.2009.42-11 so ssh sessions are working very responsible now! :)

Re: Openssh on N900
 

Yes, I can confirm this. No problems with SSH anymore. :)

Re: Openssh on N900
 

= delete =

Re: Openssh on N900
 

After installing OpenSSH Client/Server, it works pretty well for me, but there seems to be no option to turn the OpenSSH service off on the device.

Doesn't constantly running it drain the battery?

Re: Openssh on N900
 

Not really, especially if it's idle. Leaving wifi active eats far more power.

Re: Openssh on N900
 

It's power use is pretty much zero unless used.

If you've got a public IP on edge/3g like I do, other people might try guess your password though, a million times. That eats power :)

Re: Openssh on N900
 

Just remove K20ssh from /etc/rc0.d and that should stop it from loading on boot.

or

For temporary shutoff between reboots issue the following commands from terminal;

sudo gainroot
/etc/init.d/ssh stop

That would "turn it off" till next reboot or shutdown.

Re: Openssh on N900
 

Big thank you to everyone. :)

Re: Openssh on N900
 

Rather than turning off sshd, perhaps you could just configure it to use a non-standard port to reduce the chances of getting hammered by brute-force password guessing attacks?

Re: Openssh on N900
 

I hope we get Putty soon on the N900, its annoying to use the terminal always.

Re: Openssh on N900
 

Putty is terminal emulation. Whats the point to get windows app when you have native xterm?:confused:

Re: Openssh on N900
 

I'm lazy and miss the shiny buttons :P Let me rephrase it then, a SSH GUI would be nice to save the connections easily and get access without opening the terminal always.

Re: Openssh on N900
 

I too was having trouble connecting to root@127.0.0.1 , until i tried my device lock out code >.<

Who would have thought that the numerical code you put in under settings -> general -> Device lock, would be the same password that ssh uses?

Re: Openssh on N900
 

Eh? K20ssh means "Kill whatever is linked to at place 20 in the sorted order". S20ssh means to start. Removing this will prevent sshd from starting. But, preventing sshd form starting is, in my opinion, to solve the wrong problem.