In HP-UX 11.x, all telnet connections use the streams-based device files in /dev/pts/t# and need a slot from the nstrtel kernel parameter.
Each regular inbound telnet connection needs to be considered in nstrtel, including DTC so-called nailed ports in /etc/ddfa/dp.
To calculate the number, you need to set nstrtel to add up all telnet connections from PCs, other systems, DTCs with and without nailed ports, and set nstrtel large enough to cover all of them. Either use SAM or, if you increase the kernel parameter manually, call insf afterwards to create all necessary device files.
The only exception are for DTC outbound ddfa printer connections which still require a slot in npty. Rlogin uses nstrpty; terminals and modems directly attached to serial ports on the system also continue to use npty.
Since more and more subsystems are using streams-based drivers, the simplest solution is to make npty = nstrpty = nstrtel, and if you use SAM, all the needed device files will be created.
Note that if root accidently removes a device in the middle of chain (see bottom of man page: man 7 pty), then the search for an available device file terminates. Removing them and then using insf to recreate them will solve that problem. Note that this should be done from the console, ideally in single user mode since you are removing all the network connection files.
Bill Hassell, sysadmin
