#!/usr/bin/perl 
# njarj.pl : http://njarj.org/contribute.html
# typically executed "/usr/local/path/njarj.pl /var/log/maillog*"
# or "/usr/local/path/njarj.pl /var/log/messages*" from crontab
# may have to run as root to access /var/log files 

### Change this section to your specific environment ### 

#Results file: set to the full path/file-name to store results file
$filename = "/var/www/html/njabl.txt"; 

#UID and GID to own results file, from /etc/passwd
@fileown = (500,500); 

#Permissions assigned to results file, usually leave alone
$filemod = 0644; 

### Shouldn't need to change anything else ### 

#Calculate yesterday's date
localtime(time() - 24 * 3600) =~ /^\S+\s+(\S+\s+\S+)\s+/;
$date = $1;
#track found relays
%addrs = (); 

unlink $filename;
open OUTFILE, "> $filename"; 

while ($filein = shift(@ARGV)) {
 
  #open the next log file in the list
  open LOGFILE, "< $filein";  
  while (<LOGFILE>) {
    #only look at sendmail lines from yesterday
    next unless (m/$date .* sendmail.* from=.* relay=/o);
    (@line) = split /,/;
    $relay = pop(@line);
    $relay =~ m/\[(\d+\.\d+\.\d+\.\d+)\]/;
    #print the relay IP addr if we find a new one
    print OUTFILE $1,"\n" if ($1 and !defined($addrs{$1}));
    $addrs{$1} = 1;
  }
  close LOGFILE;
}
close OUTFILE; 

#set the file ownership and permissions
chown @fileown, $filename;
chmod $filemod, $filename;