How to analyze Juniper firewall logs.

HI,
Dea I set up a filter for a traffic on  my juniper firewall by:

get ff
set ff dst-port 443
Run "debug flow basic"
get db st

then I can not understand how to analyze the out put...is there any help or clearance for an example.


cheers.
besmile4everAsked:
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scardaliConnect With a Mentor Commented:
Google "screen os debug flow basic" and you'll see a Google Books result for the ScreenOS Cookbook and it will take you to the section where they walk you through the ScreenOS debug output.  

Also, I highly recommend you download the ScreenOS Concepts and Examples Volume 2.  It can be found at www.juniper.net/support, look under "Technical Documents" and then ScreenOS.  There you'll see the ScreenOS C&E Guides.  Under vol. 2 "Fundamentals" look for "Packet Flow Sequence".  That chart will make  a lot of sense if you compare it to what the ScreenOS debug output tells you but in short ScreenOS always operates in this order:

-  packet received
       *  what physical interface did the packet ingress
       *  what zone is that ingress port assigned to, this is the incoming zone
-  Existing session?  
       *  If so lookup existing session info and send packet on
       *  Otherwise continue...
-  MIP/VIP/DIP translation
-  route lookup (destination route)
       *  determine egress interface, this will be the egress zone
-  policy lookup  (is traffic allowed based on policy for ingress zone -> egress zone)
-  NAT translation
-  ARP lookup (wing ready/not ready)
-  Forward packet
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yuliang11Commented:
hi,
would that be a juniper-netscreen firewall ? just a suggestion. using syslog and sawmill would be easier  option for layer 3 and layer 4 analysis if you ask me.


http://www.sawmill.net/formats/net_screen.html
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besmile4everAuthor Commented:
Hi
I mean how to read it when I issue the command get db st?
I need to under stand its meaning...
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mindwiseConnect With a Mentor Commented:
Hi besmile....

What you're seeing is basically the decission path the juniper takes.

first thing you see is:
****int xxx packet recieved.

it fisrt tries to match the received packet to a session, if that fails, it will find the route to the destination.
With that route it knows the in and outgoing zones, and therefore knows where to look for the policy.

It then tries to find a matching policy, and use that to buold a new session, or if it fails to find any match (or finds a match that denies the traffic), it'll then drop (or reject) that traffic.

What you need to look for is
- the reason the traffic is denied, or if it's permitted, the policy that permits the traffic.

i hope this basic layout helps a bit.
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besmile4everAuthor Commented:
many thanks for your clearance...
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