Installed FB1.5 on HP-UX 11i, C3000 system. Could connect locally
using isql to database file, but would not connect using the ip
address. Could not connect using IBConsole from W2k system, but
IBConsole diagnose connection (TCP/IP) tests pass.

Finally tried to telnet to port 3050 and got two errors:
/usr/lib/dld.sl: Can't open shared library: /usr/lib/libfbembed.sl.1
/usr/lib/dld.sl: Permission denied.

Found the libs under /usr/local/firebird/lib had --x--x--x
permissions. Changed permissions to r-xr-x-rx and connection works.