SSH connection problem with 5G

[dimitris]

Hello,

It seems to be a problem connecting to router through SSH when using a wireless 5Ghz connection. I have an RT-AC66U with 380.69_2 firmware.
With previous firmwares I experienced the same problem.

When using the same SSID for 2,4G and 5G on the router (and my computer is connected to 5G), I cannot connect to router through SSH
The error I am getting from PuTTY is: 'Netwok error: Connection timed out.'
From WinSCP: 'Netwok error: Connection to "192.168.2.1" timed out.'
In router's Syslog there is no error from Dropbear (there is actually no log line during connection).

When using different SSID's for the 2,4G and the 5G the following happens:
When connected to 2,4G I can connect through SSH without problems.
When connected to 5G I cannot connect through SSH to the router. The error I can see in Syslog on router is 'Exit before auth: Error reading: Connection timed out' or 'Exit before auth: Exited normally' and a timeout on the SSH client.

Anyone else having the same issue?

Greeting,
Dimitris

 

[martinr]

How close are you to the router? Have you tried moving the computer so it is next to or in the same room as the router?

2.4GHz has better walk-penetration properties than 5GHz. See if the problem is connected with that.

 

[dimitris]

Thanks for your reply.
I tried to connect from a distance of a meter from the router (-40 dBm), but unfortunately I still cannot connect.
I can connect via telnet on port 23. If I try to connect via telnet on port 22 (ssh) I'm getting 'Connecting To 192.168.2.1...Could not open connection to the host, on port 22: Connect failed'

 

[martinr]

Thanks for the feedback. If you open Putty, under Session, top left, you’ll see Logging. Try setting Printable output on and then generating a logfile. It might tell us what the problem is.

By the way, firstly, welcome to the forum, and, secondly, XShell is preferred to Putty by many, including developers such as Merlin and thelonelycoder. So there’s a recommendation for you. But get Putty working on 5GHz first before changing anything else!

 

[dimitris]

Hi martinr,
I tried to generate a log file with Putty according to the instructions, but no file was generated. (Getting the same: 'Netwok error: Connection timed out.')

However I did install XShell too...
Output of XShell is :
'Connecting to 192.168.2.1:22...
Could not connect to '192.168.2.1' (port 22): Connection failed.'

Incidentally (no specific reason that I can say) I got this output once:
'
Connecting to 192.168.2.1:22...
Connection established.
To escape to local shell, press 'Ctrl+Alt+]'.
[14:24:59] Version exchange initiated...
[14:24:59] server: SSH-2.0-dropbear_2017.75
[14:24:59] client: SSH-2.0-nsssh2_5.0.0045 NetSarang Computer, Inc.
[14:24:59] SSH2 is selected.
[14:24:59] Outgoing packet message id: 20, length: 1403
[14:24:59] Incoming packet message id: 20
[14:24:59] Algorithm negotiation initiated... (Dialog mode)
[14:24:59] key exchange: curve25519-sha256@libssh.org
[14:24:59] host key: ssh-rsa
[14:24:59] outgoing encryption: aes128-cbc
[14:24:59] incoming encryption: aes128-cbc
[14:24:59] outgoing mac: hmac-sha2-256
[14:24:59] incoming mac: hmac-sha2-256
[14:24:59] outgoing compression: none
[14:24:59] incoming compression: none
[14:25:00] Outgoing packet message id: 30, length: 37
Socket error Event: 32 Error: 10053.
Connection closing...Socket close.
Connection closed by foreign host.
Disconnected from remote host(New Session) at 14:25:21.
'
And in router's log:
'Feb 25 14:25:13 dropbear[13606]: Exit before auth: Error reading: Connection timed out'

Unfortunately I don't have another device to connect to 5GHz (only 2,4GHz), to exclude the possibility of a malfunctioning of the WiFi card or OS. I will try to find one though.

 

[martinr]

When I tried logging with Putty for the first time s few weeks ago I had to try a couple of times. I’m not sure but I think when I opened Putty again, somehow I think the logging was turned off. And then I think I had to look for the logfile. But I persevered and it didn’t take long to get a logfile.


I hesitate to say it because it sounds stupid if it works on 2.4GHz, but are you using public-private keys? If so, perhaps log into the router and change SSH access temporarily to username and password access instead and see if that helps. I can’t see whu it should but it wouldn’t take long to try it.

 

[dimitris]

It worked, I mean the log file (had to select SSH raw mode):
'
=~=~=~=~=~=~=~=~=~=~=~= PuTTY log 2018.02.25 19:04:21 =~=~=~=~=~=~=~=~=~=~=~=
Event Log: Writing new session log (SSH raw data mode) to file: C:\Program Files (x86)\PuTTY\putty1.log
Event Log: Looking up host "192.168.2.1"
Event Log: Connecting to 192.168.2.1 port 22
Event Log: We claim version: SSH-2.0-PuTTY_Release_0.67
Event Log: Failed to connect to 192.168.2.1: Network error: Connection timed out
Event Log: Network error: Connection timed out
'

I don't use public-private keys, only user+password.

If there is progress on this I'll let you know

 

[martinr]

Dimitris, do you yhink it’s worth now connecting at 2.4GHz and logging that and then comparing the 2 logfiles?

I must say, “faiked to vonnect, network error” isn’t very helpful of Putty: you could have worked thst much out fot yourself! You want to know why or what the error is!

 

[martinr]

And let’s ask the obvious: you are still connecting to Port 22 on 2.4GHz? You didn’t change the port number? (You can see I’m clutching at straws now!)

Tge XShell logfile does seem more verbose; unfotunately, it doesn’t mean anything to me. Perhaps it will trigger a thought in another member.

 

[sfx2000]

Try using MobaXterm (free for personal use) - on the commandline - ssh -v user@host

Lot more debug happens there with the ssh client side...

FWIW - the 10053 is a winsock error suggesting a software caused connection abort.

An established connection was aborted by the software in your host computer, possibly due to a data transmission time-out or protocol error.

 

[ColinTaylor]

When using the same SSID for 2,4G and 5G on the router (and my computer is connected to 5G), I cannot connect to router through SSH
The error I am getting from PuTTY is: 'Netwok error: Connection timed out.'
From WinSCP: 'Netwok error: Connection to "192.168.2.1" timed out.'
In router's Syslog there is no error from Dropbear (there is actually no log line during connection).

Are you sure you are not connecting to a 5GHz Guest Network by mistake?

When using different SSID's for the 2,4G and the 5G the following happens:
When connected to 2,4G I can connect through SSH without problems.
When connected to 5G I cannot connect through SSH to the router. The error I can see in Syslog on router is 'Exit before auth: Error reading: Connection timed out' or 'Exit before auth: Exited normally' and a timeout on the SSH client.

These messages look like they are from when you were testing the 2.4GHz SSID. Both show that you have successfully reached the login prompt. The first message indicates that you didn't log in within the timeout period. The second message indicates that you closed the session without logging in.

 

[dimitris]

Thank you all for your help!

The culprit was a setting in Power Options of Windows 10. The power plan was set to 'balanced' and in 'wireless adapter settings -> power saving mode -> on battery:' was standing 'Medium power saving'. Changing this to 'maximum performance' solved the problem!

Weird, but if the battery voltage dropped below 16,8V then it looked like port 22 on router was closed, or the packets were malformed? or the connection was closed in the middle of negotiation. That can explain the: 'Exit before auth: Error reading: Connection timed out' or 'Exit before auth: Exited normally' (in case of voltage drop during the negotiation) or no error at all (if battery voltage was already below 16,8V), in the log of the router.

(The WiFi card is an intel AC8260 on a Lenovo laptop with preinstalled Windows 10)

 

[martinr]

Amazing! Thank you for the feexbzck.

 

[mrbagpipe]

Thank you all for your help!

The culprit was a setting in Power Options of Windows 10. The power plan was set to 'balanced' and in 'wireless adapter settings -> power saving mode -> on battery:' was standing 'Medium power saving'. Changing this to 'maximum performance' solved the problem!

Weird, but if the battery voltage dropped below 16,8V then it looked like port 22 on router was closed, or the packets were malformed? or the connection was closed in the middle of negotiation. That can explain the: 'Exit before auth: Error reading: Connection timed out' or 'Exit before auth: Exited normally' (in case of voltage drop during the negotiation) or no error at all (if battery voltage was already below 16,8V), in the log of the router.

(The WiFi card is an intel AC8260 on a Lenovo laptop with preinstalled Windows 10)

You saved me! I spent a bunch of time trying to figure this thing out. Made registry changes, enabled Keep Alives in PuTTY, you name it... This did the trick!

One question though: How did you figure it out?

Cheers!

 

[Pila]

Hello,

It seems to be a problem connecting to router through SSH I have an RT-AC66U with 380.69_2

Yes, I have Asus RT-AC66U_B1 but with 380.70 and it behaves exactly like that. But, I did not observe difference vetween bands. I normally use only 5 gHz.

If I have Web interface open, it seems to decrease sharply my chancec to ssh in. If I sshe before I open Web interface, it works well. Sometimes, Web interface does not matter.

After repeating connection attempts, I get in. Sometimes, it acts up like crazy, but sometimes it works perfectly fine. Log shows nothing at any end.

Sometimes it is just slow to connect, but rarely. It comes and goes. When it is slow, I can start putty to B1, and then go and open another putty and ssh into another router which is 8 hours and a VPN away - faster thatn B1 wil let me in.

Most often, I can ssh normally. It can work perfectly fine for days. And then get crazy. Repeated attemtps mostly resolve the problem but it may take some time to do so. None of my other routers (using 380.59) has similar issue.

Just one of several annoyances of this newer and better firmare.

 

[Pila]

It would appear that the chinese s*!$ Lenovo is to blame for me having problems with ssh / scp to the RT-AC66U_B1 fw 380.70.

ssh (putty) would simply hang and no log would appear on the router. Same for WinSCP. It would manage to connect ocassionaly after long break, say 20 seconds. Mostly not. This could go on for several minutes at a time and not occur for days.

Recently I changed my Lenovo Win7 WLAN card power settings (power management) to Maximum Performance for BOTH battery and external power. After that, I did not have a single delay or a problem connecting to the RT-AC66U_B1 with 380.70 for days now!

I am on Win7, and the same problem was present on either WLAN frequency. It did not matter that only Battery powered WLAN did not have its seting on Maximum performance and I was using it on external power.

But: I have other routers Ac56 and AC68 with older fw (380.59). Now that I think about it, it would happend that I can not ssh to them, but it would be extremely rare so I did not even react or notice it as a problem for 3 years! But with them, I would never be unable to connect putty for minutes like with RT-AC66U_B1 and fw 380.70!

So, the router with newer firmware become more sensitive to this issue. But If the problem does not return, I am asigning all the blame to the chinese s*!$ Lenovo and its s*!$y power management for the WLAN card Intel Dual Band Wireless-AC 8260.

Maybe this helps somone else

 

[Grisu]

It would appear that the chinese s*!$ Lenovo is to blame for me having problems with ssh / scp to the RT-AC66U_B1 fw 380.70.

ssh (putty) would simply hang and no log would appear on the router. Same for WinSCP. It would manage to connect ocassionaly after long break, say 20 seconds. Mostly not. This could go on for several minutes at a time and not occur for days.

Recently I changed my Lenovo Win7 WLAN card power settings (power management) to Maximum Performance for BOTH battery and external power. After that, I did not have a single delay or a problem connecting to the RT-AC66U_B1 with 380.70 for days now!

I am on Win7, and the same problem was present on either WLAN frequency. It did not matter that only Battery powered WLAN did not have its seting on Maximum performance and I was using it on external power.

But: I have other routers Ac56 and AC68 with older fw (380.59). Now that I think about it, it would happend that I can not ssh to them, but it would be extremely rare so I did not even react or notice it as a problem for 3 years! But with them, I would never be unable to connect putty for minutes like with RT-AC66U_B1 and fw 380.70!

So, the router with newer firmware become more sensitive to this issue. But If the problem does not return, I am asigning all the blame to the chinese s*!$ Lenovo and its s*!$y power management for the WLAN card Intel Dual Band Wireless-AC 8260.

Maybe this helps somone else

Use same 8260 in pcie-adapter in my PC with no problems now. SSH via powershell ssh.