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Sudden Traffic Spikes: The Top 5 Causes

Dirk Paessler

When IT departments implement network monitoring tools, they get swarmed with data that they did not have before. This new information gives them the power to act on problems intelligently, oftentimes before they end up affecting end users. The challenge, of course, is to move quickly to identify what issue is causing the problem.

One of the most common problems network monitoring tools are employed to solve are problems with bandwidth. Availability is critical for IT departments of all sizes, and slow bandwidth creates productivity problems and even outages that have a real effect on businesses. Identifying the problems behind bandwidth drains can be difficult, so to help, I’ve put together a list of the five most common causes of sudden traffic spikes.

1. Mail Server Issues

It is not uncommon for a remote mail server to continuously deliver the same email through a company’s servers, even if the target recipient denied acceptance. Incompatibility between the two SMTP implementations creates a sort of endless feedback loop that sees the same email going through the server every five minutes, chewing up bandwidth in the process. The solution involves accessing the target mail server to deny access rights to the remote server.

2. Antivirus

Many of the causes of sudden traffic spikes are security-related, be it malicious traffic, DNS attacks, or sometimes, even the AV itself. Virus scans and software updates distributed inside the LAN are a very common source of traffic spikes, and can be easily dealt with by changing scan settings and performing updates during non-critical business hours.

3. Malicious Traffic

Malware outbreaks and hacking attempts can cause spikes in network traffic, often to either mask other malicious activity or because the malware is attempting to force login to devices.

4. Scheduled Backups

Many backup products are scheduled to run at certain time intervals, or at certain times of day. They also are very network intensive, and if the timing is off, can sop bandwidth during working hours.

5. Remote Backup

Some IT departments opt to use cloud-based tools for backup. While those present certain advantages, one disadvantage is that uploading massive backups to the cloud causes serious load issues. Similar to on-premises backups, these need to be scheduled carefully and performed off-hours.

These are not the only causes of traffic spikes, but it is a good example of common and preventable problems that plague networks. Some problems are more serious and involve hardware failures or router issues, which need to be handled with care and can require spending on new equipment.

In all cases, it is critical for IT departments to establish a baseline for their network traffic so they can understand when it is peaking, and set up appropriate alerts to notify them. Alerting, combined with mapping that identifies where problems are coming from, empowers IT admins to quickly and efficiently troubleshoot most any problem.

Dirk Paessler is CEO and Founder of Paessler AG.

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Sudden Traffic Spikes: The Top 5 Causes

Dirk Paessler

When IT departments implement network monitoring tools, they get swarmed with data that they did not have before. This new information gives them the power to act on problems intelligently, oftentimes before they end up affecting end users. The challenge, of course, is to move quickly to identify what issue is causing the problem.

One of the most common problems network monitoring tools are employed to solve are problems with bandwidth. Availability is critical for IT departments of all sizes, and slow bandwidth creates productivity problems and even outages that have a real effect on businesses. Identifying the problems behind bandwidth drains can be difficult, so to help, I’ve put together a list of the five most common causes of sudden traffic spikes.

1. Mail Server Issues

It is not uncommon for a remote mail server to continuously deliver the same email through a company’s servers, even if the target recipient denied acceptance. Incompatibility between the two SMTP implementations creates a sort of endless feedback loop that sees the same email going through the server every five minutes, chewing up bandwidth in the process. The solution involves accessing the target mail server to deny access rights to the remote server.

2. Antivirus

Many of the causes of sudden traffic spikes are security-related, be it malicious traffic, DNS attacks, or sometimes, even the AV itself. Virus scans and software updates distributed inside the LAN are a very common source of traffic spikes, and can be easily dealt with by changing scan settings and performing updates during non-critical business hours.

3. Malicious Traffic

Malware outbreaks and hacking attempts can cause spikes in network traffic, often to either mask other malicious activity or because the malware is attempting to force login to devices.

4. Scheduled Backups

Many backup products are scheduled to run at certain time intervals, or at certain times of day. They also are very network intensive, and if the timing is off, can sop bandwidth during working hours.

5. Remote Backup

Some IT departments opt to use cloud-based tools for backup. While those present certain advantages, one disadvantage is that uploading massive backups to the cloud causes serious load issues. Similar to on-premises backups, these need to be scheduled carefully and performed off-hours.

These are not the only causes of traffic spikes, but it is a good example of common and preventable problems that plague networks. Some problems are more serious and involve hardware failures or router issues, which need to be handled with care and can require spending on new equipment.

In all cases, it is critical for IT departments to establish a baseline for their network traffic so they can understand when it is peaking, and set up appropriate alerts to notify them. Alerting, combined with mapping that identifies where problems are coming from, empowers IT admins to quickly and efficiently troubleshoot most any problem.

Dirk Paessler is CEO and Founder of Paessler AG.

Hot Topics

The Latest

Businesses that face downtime or outages risk financial and reputational damage, as well as reducing partner, shareholder, and customer trust. One of the major challenges that enterprises face is implementing a robust business continuity plan. What's the solution? The answer may lie in disaster recovery tactics such as truly immutable storage and regular disaster recovery testing ...

IT spending is expected to jump nearly 10% in 2025, and organizations are now facing pressure to manage costs without slowing down critical functions like observability. To meet the challenge, leaders are turning to smarter, more cost effective business strategies. Enter stage right: OpenTelemetry, the missing piece of the puzzle that is no longer just an option but rather a strategic advantage ...

Amidst the threat of cyberhacks and data breaches, companies install several security measures to keep their business safely afloat. These measures aim to protect businesses, employees, and crucial data. Yet, employees perceive them as burdensome. Frustrated with complex logins, slow access, and constant security checks, workers decide to completely bypass all security set-ups ...

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In MEAN TIME TO INSIGHT Episode 13, Shamus McGillicuddy, VP of Research, Network Infrastructure and Operations, at EMA discusses hybrid multi-cloud networking strategy ... 

In high-traffic environments, the sheer volume and unpredictable nature of network incidents can quickly overwhelm even the most skilled teams, hindering their ability to react swiftly and effectively, potentially impacting service availability and overall business performance. This is where closed-loop remediation comes into the picture: an IT management concept designed to address the escalating complexity of modern networks ...

In 2025, enterprise workflows are undergoing a seismic shift. Propelled by breakthroughs in generative AI (GenAI), large language models (LLMs), and natural language processing (NLP), a new paradigm is emerging — agentic AI. This technology is not just automating tasks; it's reimagining how organizations make decisions, engage customers, and operate at scale ...

In the early days of the cloud revolution, business leaders perceived cloud services as a means of sidelining IT organizations. IT was too slow, too expensive, or incapable of supporting new technologies. With a team of developers, line of business managers could deploy new applications and services in the cloud. IT has been fighting to retake control ever since. Today, IT is back in the driver's seat, according to new research by Enterprise Management Associates (EMA) ...

In today's fast-paced and increasingly complex network environments, Network Operations Centers (NOCs) are the backbone of ensuring continuous uptime, smooth service delivery, and rapid issue resolution. However, the challenges faced by NOC teams are only growing. In a recent study, 78% state network complexity has grown significantly over the last few years while 84% regularly learn about network issues from users. It is imperative we adopt a new approach to managing today's network experiences ...

Image
Broadcom

From growing reliance on FinOps teams to the increasing attention on artificial intelligence (AI), and software licensing, the Flexera 2025 State of the Cloud Report digs into how organizations are improving cloud spend efficiency, while tackling the complexities of emerging technologies ...

Today, organizations are generating and processing more data than ever before. From training AI models to running complex analytics, massive datasets have become the backbone of innovation. However, as businesses embrace the cloud for its scalability and flexibility, a new challenge arises: managing the soaring costs of storing and processing this data ...