[lug] ssh login error

Lee Woodworth blug-mail at duboulder.com
Mon Jan 8 21:41:00 MST 2007

D. Stimits wrote:
> Steve Webb wrote:
>> I had a similar experience on a hosted server (vmware-type situation) 
>> where they limited the number of PTYs that I had (I was running GNU 
>> 'screen' and ran out of PTYs pretty quickly).  I asked the hosting 
>> company to adjust the number of PTYs so I could spawn more 'screen' 
>> sessions and it kind of went away.
> Everything seems to center on this, but I know the CentOS kernel is not 
> a dumbed-down kernel, so I can't imagine I have to recompile for pty's. 
The kernel has an option for legacy unix ptys (probably not the exact name).
This enables /dev/ptys. It doesn't have to be enabled. I don't have any
/dev/ptys on my systems, they use the newer device names and the devpts file

Check for the character device /dev/ptmx (c 5 2) root, root 0666
and the /dev/pts dir. These are signs you have the newer pseudo
terminal setup. Also a plain mount command would show this line:
    devpts on /dev/pts type devpts (rw)
The newer setup creates the /dev/pts/<n> dir entries as needed.
They will have the ownership of the login using the pty.

Don't know why you are having issues. There are consoles, virtual terminals, and
pseudo terminals that one can use for login. I think gettys manage the
console and the virtual terminals ctl-alt-fn<1....7>. Net daemons like
ssh use pseudo terminals for the I/O.

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