Dears,

Is it possible to use ontape informix utility to backup a local database on a tape connected to a remote server? I know this possible in case of using ufsdump.

Best regards,

Yes you can on Unix.
Set TAPEDEV in the onconfig to hostname:/dev/st0
Ensure TAPESIZE is non-zero
Set up trust relationship so the machine with the backup device trusts the machine with the instance - I do this with .rhosts and the permissions of this file are critical. You can prove .rhosts is working by running rlogin from the instance host to the host with the backup device - if you are not prompted for a password then the trust works.