[Angel_Heart]

A few questions about SR5... I have CRB and Data Trails, but no other Matrix books (such as Killcode)
   (1) In 4th Ed., Node's recorded everything that transpired in them via Data Logs. Hackers had the capability to alter these Data Logs to erase their trail. I've only read one passage that very briefly mentioned Data Logs in... oh boy, I think it was someone near the end of Data Trails. My question is does anyone know if 5th Ed. uses Data Logs?
   (2) Do Hosts, beyond Matrix Perception, have a way of recording a decker's cyberdeck's commcode whenever he pops in for a snoop or visit otherwise? (Such as a Data Log...)
   (3) Do any of the books talk about rewriting or disguising a deck or commlinks commcode (essentially its IP address [digital fingerprint])? 4th Ed. had something for this but it's been so long since I played it that I don't remember the mechanics.

[fseperent]

1. I think so
2. no
3. not that I saw

[Grizzly]

Can't answer to questions 1 and 2.

For 3: As far as I understand it this is covered by the 'Reboot' action.  You don't disguise your digital fingerprint since you need one to be able to use the matrix.  What you do, once you've finished with your illegal shenanigans, is get a new fingerprint by wiping out the old one and re-registering your deck on the matrix as a brand new (and different) device.

To clarify - the 'digital fingerprint' to get on and use the matrix appears (to me) to be different than a 'commcode' which is basically just a combination telephone number/email address.

Not everyone agrees on this point - but it's what I get out of the rules and the fluff. YMMV.

[Iron Serpent Prince]

(3) Do any of the books talk about rewriting or disguising a deck or commlinks commcode (essentially its IP address [digital fingerprint])?

Not as of yet, and it is one of the reasons GMs have to run Matrix Security like they are dumber than Keystone Cops to give their players a fair shake.

Fail a Sleaze test (such as Hack on the Fly)?  The owner of the device host (and/or corporate security) get alerted to an intrusion attempt.
Owner/Corporate Security runs a Matrix Perception check against "devices other than this one (or a whitelist of corporate devices) that I/Corporate has a MARK on" and with one success spot the failed hacker.
If they get a second hit on the Matrix Perception check, they grab the commcode* and always "know something about the hackers icon" to make Matrix Perception checks to spot them on the Matrix.

The only sure fire way to lose that commcode is to replace your deck.
Everything else, is purely GM whim.

*As a bonus, Corporate Security can pass the commcode off to a Host equivalent of an Agent to run Matrix Perception checks for every n time periods - alerting Corporate Security when they are online to be traced.

[BeCareful]

There aren't any solid rules about commcodes in Core, or even in either of the expanded Matrix books that I've read, so I feel like this is another thing that GMs should hand-wave or house-rule.
So, the IT analyst from the office building you infiltrated managed to get your commcode, and can tell whether you're online or not with a Matrix Perception test looking for the persona/device with that commcode.
So, what then? You need marks to trace the physical location of that icon. With just the commcode, you can really only send messages. Plus, once you've escaped, corporate's probably going to want to focus on damage control, since there's no profit in pursuit. Right now, I can think of two potential ways to handle this:

Black Trenchcoat: "I forward any calls through my burner commlink, which I'll replace as necessary after every couple of runs."
Pink Mohawk: "You get another call from Aztechnology, asking when you're planning on turning yourself in."
"That's it, I'm blocking & un-friending them!"

[Stainless Steel Devil Rat]

Commcodes are functionally obsolete by SR5.  Persona is what's relevant in a rules mechanics-sense.

[Iron Serpent Prince]

So, the IT analyst from the office building you infiltrated managed to get your commcode, and can tell whether you're online or not with a Matrix Perception test looking for the persona/device with that commcode.
So, what then? You need marks to trace the physical location of that icon. With just the commcode, you can really only send messages. Plus, once you've escaped, corporate's probably going to want to focus on damage control, since there's no profit in pursuit.

What then?

You get MARKs.  Once you spot an icon with Matrix Perception, you can hack it.  You can get MARKs to do whatever to it, such as Trace Icon on it.  Hell, if you are badass enough you can use Reckless Hacking to do that without MARKs.

Silencing the hacker plus any and all with her is the penultimate in damage control.  If you do it fast enough, whatever was exfiltrated is completely squashed.  If you don't do it fast enough, you can make money off of selling the info to someone else.

"Boss?  That hacker that hit us last week is online again.  I've traced it's location to MegaMegaCorp.  I don't know if they are working for or against MegaMegaCorp."

"Oh?  Let MegaMegaCorp know that they are there.  At best they will owe us a favor, and at worst they will know we know they are behind their hit if the hacker works for them."

[BeCareful]

That sounds more like an opportunity for a follow-up run: you get a commcall from someone in your previous run site, asking if you could extract them and put them in a better job before they get laid off as part of damage control. Or they want to join you.

Because someone using company resources to go on a wild goose chase against a team of SINless nobodies who already got away? On company time? Sounds like inefficient working to me.

Also, since the way the Voodoo Matrix works means that your Persona can't have Identity Theft done to it, nor reliably tracked (and Stainless Steel Devil Rat mentioned the Persona's what's relevant, not commcode), it looks like that's the basic presumption.

Also again, I don't want to play it like, "The Spider makex Matrix Perception, gets two hits, and gets your commcode. He's going to Send To All, RE: This Guy, giving you a point of Public Awareness! Oh? You shoot him? Then you get a point of Notoriety for murdering an employee who never even did a single box of Matrix damage to any of your devices!"

I think this discussion has been played out and given Official Answers, but if anyone else as any run-enabling ideas, go for it!