Re: [logs] PIX logging

From: Brian Ford (brfordat_private)
Date: Tue Jul 29 2003 - 13:17:56 PDT

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    Marius,
    
    I think you've made a great start.
    
    What I would suggest next would be to ask yourself a few (at least these 
    10) questions about the log data before you.  The first time you do this it 
    could take a day (or more).  But eventually you will be able to do this 
    within 20 minutes.  It often depends on what tools you are comfortable with 
    and use.
    
    Q1: How many log messages were recorded today? (#)  Make a record of that 
    number of a calendar or in a journal.  It is the starting point for your 
    log analysis.
    
    Q2: Is that more or less messages than the day before?  How much more or 
    less (%)?  This helps you figure out if things are normal and running 
    within a set baseline.
    
    Q3: Is that more or less messages than the same day last week?  How much 
    more or less (%)?  This is a check that I do to check to make sure that my 
    baseline doesn't drift too badly.
    
    Q4: Can you explain why for Q2 or Q3?  If you see much more data today in 
    both the day and the week before; you need start asking yourself some more 
    questions like was there a rule that blocked many connections (in PIX v6.3 
    look for message 106023); is someone scanning the Firewall and creating 
    lots of half dead connections (they have associated message numbers too); 
    or do I have the log level set too high.  If you see much less data you 
    need to figure out if something is broken or mis-configured (or if today is 
    the day after a day off or holiday).
    
    Q5:  What is the message breakdown by level?  Lots of web surfing (normal 
    activity) generates lots of level 6 and 7 messages.  That might explain an 
    increase in the number of log messages aggressive surfing).  Or it could be 
    scans (level 3,4,5 messages).  Or bad rules (if I just modified the 
    rules).  Again, establish a baseline of "normal" activity.
    
    Q6: Am I seeing (m)any messages that indicate hardware or configuration 
    issues?  Those would be at the lower levels (1,2,3).  Some people make this 
    Q2 when they first install their PIX until they get used to it.
    
    Q7:  Did you see PIX v6.x Syslog message ID 199002 in the log?  Can you 
    explain why that is in there?
    
    Q8: Are there any new messages that I have not seen before?  if so, why are 
    they there?
    
    Q9:  What is the top denied protocol? How did it get denied?
    
    Q10:  What are the top 5 denied IP addresses?  How did they get denied?
    
    These are just ten of the rules that I talk about and often use.  I have 
    like 30 more solid rules written down somewhere.
    
    Liberty for All,
    
    Brian
    
    
    At 11:27 AM 7/29/2003 -0700, Marius Baicoianu wrote:
    >Hi,
    >
    >I have red your messages in reference with the PIX
    >logging and I would like to ask you few things:
    >- after you configure syslog and logrotate to log and
    >rotate my system logs what do I do next?
    >- do you have a easy way to review these logs? scripts
    >or procedures? I'am able to have all the PIX logs on a
    >syslog server, and I am able to cut them daily, but I
    >don't know what I suppose to do next....How can I
    >review so much info?
    >
    >Please help.
    >Thanks.
    >
    >
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