I can't make up my mind on this. One of my PCs is walking around (unknowingly) with a swiss cheese virus munching on his firewall and one more bite will put it at rating 0.

So, is there still a firewall with a rating of 0 or has the program simply disappeared?

For most aspects the difference is trivial, but what about account levels? Would you still make it a threshold of 6 to get an admin account, or would you reason that without a firewall there's nothing to stop every Tom, Dick and Sammie's icon from waltzing in and taking over? Is exploit even needed?

Can you think of any other implications?

Well...how secure are our computers today when the firewall and virusprogram, pop-up stopper and Ad-ware stoppers are turned off?

I would imagine that the firewall rating incorporates all those program and when it is at zero it is effectively turned off.

One thing that jumps to mind is that with a simple Analyze check, every Tom, Dick, and Harry could TELL that this character is walking around with a zero-firewall. In fact, if the character thought to analyze his own node/icon, he could ask that question, as well - but I doubt he would. Basically, he would be advertising the fact that he is easy pickings (and a computer n00b). He's bound to get hacked a lot, easily, and this might tip him off the 3rd or 4th time some 12 year old takes over his comm.

Unless of course the crappy commlink quickly becomes a home for a lost AI who slays the virus and improves the commlink and fixes a lot of things for the character...not without repercussions for the character of course.

Having to negotiate with ones own commlink to get ones weekly "allowance" might lower his rep somewhat among other runners...

People still cannot access your PC just because your firewall program is down, some sort of exploit if still needed. Sure, the matrix is not the internet, but without an exploit (or legitimate accout) I wouldn't let anyone gain access to a commlink.

All it means is that he can't detect any intrusion.

Not really, Matrix Perception is not based upon your firewall, and if you had an Analyze program actually running, you would still get to roll the Analyze to detect the intrusion... Though with a Firewall of 0, the chances are good thet the attacker will penetrate long before a Matrix Perceprtion test is called for...

What it really means, though, is that access to such a comlink's user account is a threshold of 0 (though you would still need to make the exploit roll of course) and Security is Threshold 3, with Admin Access a Threshold of a measly 6... which effectively means that you will probably have whatever access you need to quell any other response, if one ever actually materializes...

Keep the Faith

The detection roll is analyse + firewall and he has an analyse program. So, would he just roll analyse dice to detect intrusion or would he automatically fail because there's no firewall?

Suppose he has no firewall and no analyse and someone tries to hack in without the stealth program (like a sprite, say) which is normally an automatic success - is the intrusion detected then?

While it is clear for Skill + Attribute dice pools that there are "no default" skills which prohibit the roll of the dice pool, this is no clear for other types of Dice pools made from different base combinations.

What happens with Skill + Program is one is zero? Can you use a skill without the program? Can you use the program without the skill? If you don't have the skill, can you replace it with the attribute? The rules aren't explicit.

What do you do when the test is Software(Analyze) + Matrix Attribute(Firewall) and one is zero?

Personally, and this is my opinion, not RAW, unless it's specifically prohibited, I see no reason to at least allow a die roll, even if one of the pair is 0. For Skill + Program and no skill, I allow rolling program, but not the replacement of the Skill portion with (attribute - 1).

I know you can't use a program+skill combination if you don't have the program, UNLESS you get that quality from Unwired where you can choose a program you can roll without it, just with the skill.

If he has no firewall and no analyze, he gets no dice to the check to detect a break-in - I think that means that the intrusion is not detected.

It's sort of zen, though - if someone with no agility and no skill shoots someone with no reaction, do they hit? (The answer is no. Not that zen, I guess.)

I'd love to see the explanation on an intruder glitching his attempt to get through the Firewall of 0.

Intuitive Hacking?

Yes, that's looks like a useful case.

As a rule I never outlaw something that is explicitly RAW, but that quality flies in the face of the described functioning of the Matrix (i.e. you MUST have the appropriate program) with no explanation. An expert with Hacking 6 can't hack without at least the most basic of Exploit programs, but someone with only a rudimentary understanding of the skill IS able to replicate the functioning of the program through unexplainable means? This is one of the very few times I will denounce a quality.

I think I'd probably agree with this, but I think I would treat the program as the attribute in a defaulted test and deduct 1 from the dice pool. Plus if the skill is trained (which I think at least hacking is) then it's a total no go.

Makes sense, since it's up to the node to do the detecting rather than the intruder to prevent it.

Would the character be totally bombarded with AR Spam when ever they access anything ? Say the PCs walk into a bar and access the drink menu would the character get swamped with promotions for brands of drinks, types of cocktails, suggestions of stuffers 'that would be perfect with your drinks selection' etc ? Would their comm be loaded with adware and spyware and kiddy / store bought hacker virus ?

Umm ... how about he inserts a bit of code he forgot wasn't necessary (forgetting there was no firewall) and said code causes an attention-grabbing fault in the node? Ooh, maybe he accidentally repairs the firewall! 100% impossible, I'm sure, but if hilarity's your game ...

Perhaps he can make crude line codes on the fly? Perhaps he has some intuitive knowledge of how technomancers do what they do and he discovered a way to simulate it (although quite terribly)?
I don't think it is a bad quality nor a good quality. Most program rolls have high tresholds so rolling only your skill is not useful most of the time, but it sure can help you when you had your program destroyed/erased by someone. In this case, spending a point of edge or even burning an edge point might be the difference between life or death, but I think it is to "iffy"