Understanding the Importance of Firewall Logs for Network Security
I’m typing this after my third coffee — it’s one of those mornings where the caffeine kicks in just as the memories start dashing in. Party in the trenches from ’93, network admin from back before we’d split voice and data across PSTN muxes and 8-inch aint the only disk size we like—boy howdy have we ridden the hurricanes! The Slammer worm? I’d seen that one first-hand, a dirty little bugger that inspired me not to leave firewall security as one of those just-a-check-box-on-your-IT-list deals. These days, running P J Networks, I assist organizations, including three banks in very recent memory, in migrating or modernizing their zero-trust architectures, yet firewall logs — that old loyal soldier — are still essential.
What Are Firewall Logs?
But first things first: Firewall logs are kind of like the diary your network keeps. It logs every packet that tries to come in or go out, every connection attempt, and allowed or denied. It’s a black box on a plane except that this plane is your enterprise network.
These logs capture:
- Source IP and destination IP address.
- Ports and protocols used.
- Timestamps of requests.
- Firewall action (allow, block, reject).
If you imagine your network as a castle (yep, going full medieval here), the firewall logs are all the guards’ notes on who tried to gain access, where they came from, and which way they tried to break in. Now it is just travelers and invaders.
Back in the early 2000s, when firewalls were more straightforward and logs were less tedious to parse by hand. Today — oh boy — we’re talking gigabytes each day. But the practice stands: Without these logs, you are essentially flying blind.
How Logs Help Detect Attacks
And here’s where it gets interesting. Firewall logs are more than records; they are the eyes and ears of your cybersecurity operations. That’s where the beauty lies:
- If someone makes many attempts to connect but fails repeatedly, this can be a hint to a brute force attack.
- Traffic to odd ports could be malicious recon or data exfil.
- Unprecedented traffic coming in at strange hours is frequently a warning of DDoS or malware going viral.
I’ve worked a case where firewall logs at a bank showed a dull pattern tiny, deliberate pings to a port you wouldn’t normally look at. Logged in over weeks. Most teams probably wouldn’t have noticed. But that little observant pearl helped us nip a huge intrusion in the bud.
Logs usually say something—a problem not everyone reads well. And for the love of all things holy, don’t even get me started on those organizations with teams who don’t check firewall logs daily. That’s akin to shutting the door but leaving the window wide open and closing your eyes.
Real-Time Monitoring
Here’s the thing. Firewall logs don’t do you any good unless somebody’s looking. And not once a week (or even worse, once a month) when someone thinks to check on those logs but in real-time log monitoring itself is the game changer.
We provide live firewall log analysis by P J Networks. We’ve seen the whole gamut: from script kiddies looking for vulnerabilities to APTs attempting to be stealthy.
Why real-time?
- Real-time alerts for suspicious activity.
- Quicker reactions to possible intrusions.
- The ability to link events between different systems.
Your logs are amassing and nobody is watching — you are already in trouble. Think of it as the dashboard of your car. Also, they are not decorative: warning lights signal critical issues at this moment. Ignoring them? That’s a highway to disaster.
Log Retention Policies
Logs are not just throwaway garbage. They are your digital evidence, your forensic treasure trove should there be any incidents. But keeping everything forever? Not practical or even wise.
Compliance, cost, and security are at the center of a log retention policy:
- Regulatory: banks, health care, finance—they all have specific retention periods they require these records to be stored for.
- Your risk landscape, which your business especially faces.
- Storage and administration functions.
This is where I’ve got to admit—I’ve seen businesses cut corners and skimp on log retention in the name of saving money. Big mistake. Last year, I assisted a client in reconstructing an attack that occurred several months previously, thanks to well-kept three-month-old logs.
TL;DR: Know your retention policy and stick to it.
Best Practices
So, after nearly 30 years, here is what I would tell you — firewall security without proper log management would be like driving a car with no sideview mirrors: it is dangerous and stupid.
Best practices:
- As much logging as possible. Do not only log accepts, log anything relevant! You need a full picture.
- Automate collecting and analyzing your logs. I’m not opposed to automation but — no, when people tell me AI-enabled is a silver bullet, I’m skeptical. After all, you have expert eyes, too.
- Correlate logs from your firewall with other sources such as IDS, endpoint security, SIEMs.
- Scrutinize logs on a daily basis, or establish alerts for anomalous patterns.
- Secure your logs. If an attacker gets a foothold, they’re prime targets for tampering.
- Train your teams to know what they’re seeing. Tools without knowledge? Wasted.
I can get a little ornery when I see password policies (oh, the rants I have had!). Here is the analogy—if your firewall log was a neighborhood watch bulletin, strong passwords and access controls are the locks on your doors. One without the other? Useless.
Quick Take
- Firewall logs = heartbeat of your network.
- They demonstrate assaults before harm commences.
- Lifesaver = real-time monitoring.
- Store logs intelligently for compliance and forensic.
- Fuse automation with human expertise.
If you’re serious about cyber threat detection, add monitoring firewall logs to your “must-have” list. Yes, that’s a fact, coming from a guy who’s been sitting behind the wheel since PSTN muxing voice and data together. You don’t have to wait for your network to become the next headline.
And so, as I sit at my desk (coffee 4 kicking in), back from the hardware hacking village at DefCon where physical attack surfaces demonstrate that digital security ain’t just about code, I can’t stress this enough: logs tell you the true story of your network’s health. To lose sight of them is to be lost.
Want help? At PJ Networks, we’ve got you covered — and we’re not talking about firewalls and servers, but in-depth log monitoring that’s actually proactive. Because you don’t buy security, you do it.
And hey—sometimes, old school is best.