SKIP TO POST OF 9 February, about 16:00
I've just replaced a 2820Vn with a 2860Vn+, updated to 3.8.4.3_VT3, DSL Version 572801_A HW: A. Everything works fine in most respects, except for the following issues. I'll list them for anyone coming here from a search, but the SSH issue is my main problem, and what I'm asking about. I have no user accounts on the router, just admin.
1. The 2860 is supposed to accept saved configurations from the 2820, so long as recent firmware is used on both machines (yes). It does import the 2820 configuration, but after reboot the administration console goes back to its login page on selecting most menu options; administration is impossible. Not a major problem: re-enter configuration manually.
2. I used an old 1GB Disgo FAT32 USB stick in the 2820 to store SysLog data; it worked fine. The stick is still fine; a Windows PC finds its contents. But when the USB stick is plugged into the 2860 it kills the router until disconnected: it won't connect to the Internet or the admin console. Maybe more modern USB memory would work - haven't (yet) tried. Not a major problem; worst-case I can do without a SysLog or save it on a computer - I've never found it to be of much use.

That's all about these issues. My main issue, which is a problem to me:
3. I am unable to get to the router's command interface with SSH. I'm using exactly the same procedures - ZOC and puTTY, from Windows 10/64 - which worked on the 2820. Telnet works fine, exactly as the 2820 (including scripted access). In 2860 Management, SSH is enabled, at the default port (22). Allowing maintenance from the Internet makes no difference, using either a 192.168 LAN address or a fixed IPv4 Internet address, both of which work on the 2820. I have played with various settings including enabling and disabling IPv6, to no avail, and returned them to defaults. I need to administer the router remotely, from an IP address not known in advance, so SSH is a lot safer than telnet (mainly, I switch on local computers from a remote location by WoL). I usually use the ZOC v4 communications program to login automatically using credentials set up in its address book, but I also use puTTY manually. puTTY simply brings up a blank command window (no "Account:" prompt) and times out when used in the same way as worked for the 2820. Zoc says "[SSH] ERROR: A connection attempt failed because the connected party did not properly respond after a period of time". I played with all the puTTY settings that could conceivably make a difference, to no effect. puTTY didn't write a log, although I set it to log everything.

Making an SSH connection with puTTY is pretty simple, there isn't much to get wrong, and it works fine on the 2820. Can anybody throw light on this?

Thanks and best wishes.

Try right clicking on the Putty executable file and run as administrator even if you are logged into the Win10 PC as admin.

Otherwise I think I would do a full factory reset by reinstalling the .rst firmware again and manually reconfigure the router afresh.

If that fails given that you have several problems I would beggar the question that maybe the router is faulty.

akwe-xavante wrote: Try right clicking on the Putty executable file and run as administrator even if you are logged into the Win10 PC as admin.

Thanks, that made no difference. I didn't expect it to, as the exact same procedures worked with the 2820.

Otherwise I think I would do a full factory reset by reinstalling the .rst firmware again and manually reconfigure the router afresh.

I will eventually do that; at the moment I have more pressing matters. The latest firmware was recently installed with .rst, though that doesn't guarantee that nothing went wrong.

If that fails given that you have several problems I would beggar the question that maybe the router is faulty.

The USB stick problem is likely to have been due to the particular stick used, though OK on a PC; I have connected an even more antique 512MB FAT (not FAT32) stick, and it seems fine. so only one problem. Proper debugging of the SSH issue is too much to try; two methods that worked flawlessly with the 2820 both fail on my 2860. If there's a fault, my gut feeling is that it's firmware, and will eventually come right with updates. Before going further I'd like to ask the question: has anybody had experience, successful or not, making an SSH connection to a 2860-series with 3.8.4.3_VT3, DSL Version 572801_A HW: A? I'm connecting from subnet LAN1 (always enabled).

By the way, I'm not using the usual 192.168.0.1 or 192.168.1.1, which shouldn't make a difference (these addresses cause trouble when making a VPN with another network using the same subnet).

Best wishes
PS: I have just opened ports 22 and 23 (SSH, telnet) to Internet access and used Gibson's Shields UP to detect open ports - it found the telnet port open, but not SSH. Which is telling me the same as my experience with telnet and puTTY.

Try changing the port that is normally used for a SSH connection to something completely different and test open ports again! Test Putty again to the user defined port.

So OK now you know why using Putty is not working.

If you can establish a telnet connection is there a command you can run to verify that the SSH server on the router is in fact running? A quick google for such I command and I failed to find one.

I reported that I was unable to connect to a 2860 admin console with SSH. I've now found that this was a configuration issue. It's puzzling: I thought that it was always possible to connect by telnet, SSH, or whatever from LAN1 (not from other LANs or the Internet unless enabled). Telnet and HTTP always work fine, but not SSH.

I reinstalled the same firmware.rst and tried connecting to 192.168.1.1 with no configuration whatsoever (with computer getting address via DHCP). All methods worked (puTTY connecting via SSH merely entering address and not changing any parameters). So the router and firmware support SSH. I then reloaded my configuration file, and SSH no longer worked. Some configuration setting presumably caused this, or maybe a corruption in the .cfg file. I might eventually get to the bottom of this; for the time being I'll work without being able to make an SSH connection, there don't seem to be any other problems. Thanks for the assistance.