Debu messages in ISC???

sthaug at sthaug at
Thu Mar 29 08:55:47 UTC 2012

>                 In ISC dhcp-4.2.3 code , while running server(ipv4/ipv6) or relay(ipv4/ipv6)  if we enable -d(debug option) where would be the debug messages will be printed.
>                 Is there any separate file for storing debug message in ISC code for both IPv4 and IPv6.
>                 Please let me know.

You have already been answered, multiple times. dhcpd uses the standard
syslog mechanism for log messages, *including* debug messages.

The dhcpd man page also specifies,

  To have dhcpd log to the standard  error  descriptor,  specify  the  -d
  flag.  This can be useful for debugging, and also at sites where a com-
  plete log of all dhcp activity must be kept but syslogd is not reliable
  or  otherwise  cannot  be  used.    Normally, dhcpd will log all output
  using the syslog(3) function with the log facility set to LOG_DAEMON.

Thus you could in principle get all logging to a separate file if you
redirect standard error.

However, there is no point in asking the same question repeatedly.

Steinar Haug, Nethelp consulting, sthaug at

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