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"Defeat is not the worst of failures. Not to have tried is the true failure."

PPTP Pass-through through Juniper NS 5GT Firewall

July 16th, 2010 rsivanandan No comments

Got a question on this one in my comments page and hence thought of putting it together. Say there is a PPTP server residing on the trust side of your NS firewall (applicable to all/most of the NS firewalls running Screen OS). For simplicity, assuming that the device is in NAT mode and you want to allow connections coming from internet for PPTP VPN, follow the steps here;

First create a custom service to address the PPTP requirement (This is Microsoft windows specific);

set service CustomPPTP group "other" 47 src 2048-2048 dst 2048-2048

set service CustomPPTP + tcp src 0-65535 dst 1723-1723

The first line above creates a custom service named “CustomPPTP” with protocol number 47 (GRE) with source/destination port as 2048.

The second line adds to the same service for PPTP (port 1723 TCP).

Then the next step would be to NAT the internal PPTP server to publically accessible server using a public ip address. Here we’d use the same address assigned on the untrust interface (single public ip available scenario);

set vip multi-port

set interface ethernet0/0 vip 2048 CustomPPTP 10.1.1.10

The first line above states that it is a multi-port VIP. Normally a VIP listens only on a single port, if a single ip address is used and you want to have multiple ports forwarded, multi-port VIP is needed.

The second line above sets a VIP for port 2048 for the internal server (PPTP Server) 10.1.1.10 (assuming the ip of the internal PPTP server to be this).

almost done; the only thing pending is a policy to allow traffic to pass through this condition;

set policy from untrust to trust "any" "VIP::1" "CustomPPTP" permit

The above policy allows any machine from untrust zone (internet) to connect to VIP address (trust zone) for the service “CustomPPTP”.

Just save the configuration and you should have it working just fine…

Juniper KB Link

Categories: Juniper, VPN, Windows Tags:

Block Facebook using Juniper SRX

July 13th, 2010 rsivanandan 2 comments

Continuation to the last post of MPF on Cisco ASA series, Juniper’s nextGen firewalls (SRX series that run JunOS software) can also be used for blocking unwanted sites. While SRX supports integration to SurfControl/WebSense etc, this post is more focused on the inbuilt capabilities just like what Cisco’s ASA had.

UTM feature (Unified Threat Management) is integrated into SRX devices. So in order to block a site(s);

1. First create a custom block lists to contain the websites that you want to block.

custom-objects {
    url-pattern {
            badsite {
                    value www.facebook.com;
            }
            addictivesite {
                            value www.twitter.com;
            }
}
    custom-url-category {
        bad-sites {
            value [ addictivesite badsite ];
        }
    }
}

As you can see, the custom URL category block list above contains the site ‘www.facebook.com’ and ‘www.twitter.com’ and based on the preferences time-eating sites like facebook/twitter/myspace etc can be used in here. Again, the advantage is that it doesn’t deal with ip addresses and hence very effective how many ever servers are hosted around the world.

2. Then create a web filtering policy to allow the traffic after screening the type/site to which the traffic is going to, as below;

policies {
    from-zone trust to-zone untrust {
        policy utm {
                match {
                        source-address any;
                        destination-address any;
                        application any;
                    }
        then {
                permit {
                    application-services {
                                            utm-policy wf-block-specfic-categories;
                                        }
                        }
                    }
                }
            }
        }
utm {
    feature-profile {
        web-filtering {
            url-blacklist bad-sites; #This causes sites in the bad-sites category to be blocked

utm-policy wf-block-specfic-categories {
    web-filtering {
        http-profile block-selected-sites;
                }
        }
}

Along with this, SRX also supports usage of ‘Custom Block Messages’ and also make this time bound. Say if you don’t want to block it completely but just block it during business hours that is possible too by scheduling policies.

Categories: Access-Control, Juniper Tags: block facebook, block twitter

Modular Policy Framework (ASA)

July 5th, 2010 rsivanandan No comments

Productivity increase by blocking non-project related sites is one of the myth that I’ve seen a lot on various online forums and as well there are always counter research data as to this has nothing to do with ‘increase in productivity’. I guess, I kinda agree too (Well, I know one of the leading IT companies who doesn’t give computers with internet access to any employee and only the lead/manager has it, that too restricted).

So putting aside the arguments, one of the issues with blocking outgoing connections based on IP has always failed (imagine the cloud of servers, if you were to block say yahoo mail). Now the Modular Policy Framework does support regex checking in the URL header to see which site it is going and block it, if you’d like to.

Here is the Cisco article describing the MPF in details {Here}

Now how do you block say access to facebook or myspace, from being utilized by your employees?? Pete has a good write-up on it and hence I’m not going to write it again here.

In short the configuration you need is; Thanks to Pete for providing such a detailed write-up.

On the Global Policy
————————————————-

regex domainlist1 "facebook.com"
class-map type regex match-any DomainBlockList
match regex domainlist1
class-map type inspect http match-all BlockDomainsClass
match request header host regex class DomainBlockList
policy-map type inspect http http_inspection_policy
class BlockDomainsClass
reset log
policy-map global_policy
class inspection_default
inspect http http_inspection_policy
service-policy global_policy global
———————————————-

With its own policy

———————————————–
regex BLOCKED_DOMAIN_1 "www.facebook.com"
access-list TRAFFIC_TO_INSPECT_FOR_BLOCKED_DOMAINS extended permit tcp any any eq http
class-map type regex match-any CLASS_MAP_BLOCKED_DOMAIN_LIST
match regex BLOCKED_DOMAIN_1
class-map type inspect http match-all CLASS_MAP_DEFINE_TRAFFIC_TO_INSPECT
match request header host regex class CLASS_MAP_BLOCKED_DOMAIN_LIST
class-map CLASS_MAP_HTTP_TRAFFIC
match access-list TRAFFIC_TO_INSPECT_FOR_BLOCKED_DOMAINS
policy-map type inspect http POLICY_MAP_HTTP_INSPECTION
parameters
class CLASS_MAP_DEFINE_TRAFFIC_TO_INSPECT
drop-connection log
policy-map POLICY_MAP_OUTSIDE_INTERFACE
class CLASS_MAP_HTTP_TRAFFIC
inspect http POLICY_MAP_HTTP_INSPECTION
service-policy POLICY_MAP_OUTSIDE_INTERFACE interface outside

Categories: Cisco, Tech in general Tags: block facebook, cisco asa, modular policy framework

Photography – Gears

June 18th, 2010 rsivanandan 2 comments

I’ve been lately pretty much exploring my photography skills, a long lost ambition now kind of came true. Simple reason, I can afford to buy these now which I couldn’t earlier.

A Nikon D-5000 is what I have, It is a Prosumer Camera (Professional + Consumer), after much research found that this one would be ideal for a beginner like me, who’d love to have the professional SLR options to some level so that it doesn’t overwhelm me too much and of course the damage on the pocket too.

Comes with a Kit Lens which is 18-55MM AF-S lens, the D-5000 doesn’t have an inbuilt motor so I have to buy lenses that have the motor built-in, means a little more money involved.

Then I also bought a telephoto zoom lens (55-200MM), which does a pretty good job. In fact this lens seems to fare much better than the kit lens for the similar kind of shots. I’m a newbie and still can find out the difference.

It is a lot of fun and pain at the same time.

I’ve learnt that you click 50 shots to get one shot perfect, just the way you want it and you’d know Planning on investing more time doing this. I’ve uploaded some of the photos that I thought are good onto http://fotoblog.rsivanandan.com