Hi there, I'm using a Synology DS101J nas with linux on it. I saw that there was open ssh 4.2, so i upgraded to the last 5.X version. I linked the right sshd_config, i have passwordAuthentication yes, permitrootlogin, and allowedUsers admin root

I can log with admin, but not with root, but that's the strange thing:
root is meant to have the same pass as admin does, but the /etc/shadow entry is different, but i can login using telnet or the webinterface using the admin password with the root user. I don't want to change the root pass because i'm afraid I'll break something, cause it's a special distribution for a NAS.

Maybe there's a tricky configuration with telnet, but there's no telnetd.conf so I assume the defaults parameters are used.

Thanks for your advices guys.

I believe that the correct format for the root login parameter is:
Changing that >>should<< allow the root login.

I do not believe that you have to additionally use "AllowedUsers" for root.

I can't imagine that doing a 'passwd' as root would break anything . . . the hash in shadow for each being different does not necessarily mean that the passwords aren't the same.

As far as I know, root login is not allowed in telnet by default, so that is an odd telnetd or there is a config file somewhere.

The salt (the first part what you see as password in /etc/shadow)) that is used for the for the password hashing is different and therefore the total password that you see is different.

If I understand you correctly, you CAN login as root but not when you use SSH? If so, keep it like that, use admin (or another user to login) and use su - root. It's a lot safer and even if that box is not connected to the big bad world it's still a good habit.

Thanks for your help, but it still not work:

login: admin
...
partage> su root
su: This applet requires root priviledges!
partage> su - root
su: This applet requires root priviledges!

I've put the right PermitRootLogin, I've uncommented it in sshd_config.
All the config is the sshd_config by default, exept i set the permitrootlogin, allowusers, and PasswordAuthentication yes

For the telnetd, i typed find / | grep telnetd.conf and there's nothing. Also check inetd.conf, but no referecence to any configuration file

The thing is that is used to work before I upgraded the version of openssh.

Just to point out that su and ssh have nothing to do with each other. See also sudo. They are separate cmds.

Just to be completely clear . . . it does say, "PermitRootLogin yes" in your sshd_config file? Just "PermitRootLogin" is not sufficient, I do not think.

The prompt, "partage>" . . . is that how your shell prompt has always looked on that machine?

If just "su" is really not working, perhaps "sudo su -" and enter the password for the admin user when prompted . . . depends on the configuration of the sudoers file and the permissions on the su executable as to what will work and for whom.

To sidestep all of that, though, if "PermitRootLogin yes" is in sshd_config, you should be able to log straight in as root with a simple "ssh root@hostname"

As pointed out earlier, it is preferable from a security point of view to log in as a less privileged user and then set UID to root.

yes, I set PermitRootLogin yes, partage> is the right prompt (was using telnet as root, local personnal network, not so crazy )

when I type su - or su root it gave me the message above, and the sudo command doesn't even exists...
Maybe i have to set UID root to my admin user to be able do make a su - root ? But how to do so ? I'm quite new in unix administration

You have to know that's a very minimalist distro, acting more as a firmware with extended function as you have in linksys WRT54G for example.

passwd root does the trick, but's if someone got an idea why did it works with telnet, but not with ssh, I'm really curious about that...