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TTY Locked-Answer

© July 2003 Tony Lawrence

This is the answer to TTY Locked

SCO OSR5 will lock out a tty after too many unsuccessful logins. That's a security feature, and you can set the number (or disable it entirely) in the SCOAdmin Terminal Manager. Cleaning a keyboard is a great way to generate unsuccesful logins, so that was my first guess.

The user had turned everything off before cleaning, but afterwards the ENTER key was stuck down for a while, and that caused ttyp2 to become locked.

But why could Jim login when apparently no one else could?

It was just a matter of lucky timing. Here's what happened:

When Al (or anyone) telneted to the box, the next available tty was ttyp2, so that was used. The moment Al logged in, he was kicked out because ttyp2 was locked, which made ttyp2 the next available tty again, and the cycle continued.

However, while the login prompt was being displayed, before Al actually logged in, ttyp2 was in use (by login), so ttyp3 became the next available terminal. Jim happened to log in during that period, so he got in successfully. The next person to try would get the available ttyp2 again (SCO OSR5 always uses the lowest available), so they'd get kicked out.

The simple fix was for Al to make a connection, but not login, then make another connection. His first would tie up ttyp2, so the second would get p3, where he could login and type:

/etc/ttyunlock  ttyp2

Al could have llogged in at the server console too, but that room was locked and a long way from his desk, so we did it this way.

Another command to know for SCO:

usermod -x "{administrativeLockApplied 0}" -x "{unsuccessfulLoginAttempts 0}" username

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