On-Net Surveillance Systems, Inc.
NetDVMS 6.5f User Manual
Video Device Drivers
215
Log File Structures
Most log files generated by NetDVMS use a shared structure complying with the W3C Extended Log
File Format. Each log file consists of a header and a number of log lines:
•
The header outlines the information contained in the log lines.
•
The log lines consist of two main parts: the log information itself and an encrypted part.
The encrypted part makes it possible—through decryption and comparison—to assert that a
log file has not been tampered with.
Integrity Checks and Possible Error Messages
Log files are subjected to an integrity check once every 24 hours. The result of the integrity check is
automatically written to a file named according to the structure LogCheck_YYYYMMDD.log, e.g.
LogCheck_20070615.log. The log check file is by default placed in the folder containing the NetDVMS
software.
Any inconsistencies will be reported in the form of error messages written in the log check file. The
following table lists possible error messages (other, non-error, messages may also appear in the log
check file):
Error Message
Description
”Log integrity information was not found.
Log integrity can't be guaranteed.”
The log file could not be checked for integrity.
”Log information does not match integrity
information. Log integrity can't be
guaranteed.”
The log file exists, but does not contain the
expected information. Thus, log integrity cannot
be guaranteed.
”[Log file name] not found.”
The log file was not present.
”[Log file name] is empty.”
The log file was present, but empty.
”Last line changed/removed in [log file
name].”
The last line of the log file did not match
validation criteria.
”Encrypted data missing in [log file name]
near line [#].”
The encrypted part of the log line in question
was not present.
”Inconsistency found in [log file name] near
line [#].”
The log line does not match the encrypted part.
”Inconsistency found in [log file name] at
beginning of log file.”
The log file header is not correct. This situation
is most likely to occur if a user has attempted
to delete the beginning of a log file.
