Fixing Time-Specific Server Connection Dropouts on Minecraft

You test your server at 9 AM and everything runs fine. Players join, chunks load, ping is stable. Then around 12 PM or 1 PM, connections start dropping. Players get kicked with "Connection Lost" or "Timed Out" errors. You restart the server. It works for 20 minutes, then drops again.

You already tried changing your DNS to 8.8.8.8. You flushed the DNS cache. You disabled your firewall. Nothing helped.

This problem is not random. It follows a pattern because it has a specific cause. Here are the four most common ones.

---

Cause 1: ISP Peak-Hour Throttling

Internet service providers manage bandwidth across their networks. During off-peak hours (early morning, late night), you get the full speed you pay for. During peak hours (noon to 10 PM), many ISPs deprioritize gaming traffic because it uses persistent connections on non-standard ports.

Your Minecraft server runs on port 25565 by default. ISPs know this port. Some throttle it during busy hours to prioritize web browsing and video streaming traffic.

How to test this:

1. Run a continuous ping to your server IP during both working and broken time periods
2. Compare the results. If morning ping is 20ms and afternoon ping jumps to 200ms+ with packet loss, your ISP is throttling

ping -t your.server.ip

On Linux or Mac, use:

ping your.server.ip

Leave it running and check the results after the "dropout window" starts.

How to fix it:

• Change your server port to something less obvious. Port 443 (HTTPS traffic) or port 8080 rarely get throttled because ISPs treat them as essential web traffic
• If you are self-hosting, use a VPN tunnel between your PC and the server to encrypt traffic so the ISP cannot identify it as Minecraft
• If you are on hosted infrastructure like Space-Node, your host already runs on optimized routes that ISPs do not throttle

---

Cause 2: Dynamic IP and DHCP Lease Expiration

Most home internet connections use dynamic IP addresses. Your ISP assigns you an IP address through DHCP, and that assignment has a lease timer. When the lease expires, your router requests a new one.

Many ISPs set lease timers to 12 or 24 hours. If you got your IP assignment at midnight, it expires around noon. During the renewal, your public IP address changes. Every player connected to the old IP gets disconnected instantly.

How to test this:

1. Check your current public IP at whatismyip.com right now
2. Check it again when the dropouts start
3. If the IP changed, this is your problem

How to fix it:

• Log into your router and look for a "DHCP Lease Time" setting. Some routers let you request a longer lease
• Ask your ISP for a static IP address. This costs a few euros per month but permanently fixes the issue
• Use a dynamic DNS service (like No-IP or DuckDNS) so your server domain automatically updates when your IP changes. Players connect via the domain name instead of a raw IP

---

Cause 3: Router NAT Table Overflow

Your home router maintains a NAT (Network Address Translation) table that tracks every active connection passing through it. Each Minecraft player connection creates multiple entries in this table. Budget routers from ISPs typically handle 1,000 to 4,000 NAT entries before they start dropping connections.

During the morning, your household uses minimal connections. By afternoon, every device is active. Smart TVs streaming, phones syncing, laptops browsing. Each browser tab alone creates 5-15 NAT entries. Add a Minecraft server with 10-20 players and you hit the router's limit.

When the NAT table is full, the router silently drops the oldest or lowest-priority connections. Minecraft connections get dropped first because HTTP traffic is prioritized.

How to test this:

• Log into your router's admin page (usually 192.168.1.1)
• Look for "NAT Sessions" or "Connection Table" in the status page
• If the count is near the maximum when dropouts happen, this is the cause

How to fix it:

• Replace your ISP router with a proper networking device that handles 32,000+ NAT sessions
• Reduce the NAT session timeout for UDP traffic from the default (often 300 seconds) to 60 seconds to clear stale entries faster
• The permanent fix: host your server on external infrastructure. A VPS or dedicated server at a datacenter does not route through your home router at all

---

Cause 4: Server Process Memory Pressure

If you self-host, your server's Java process grows in memory usage over time. Java allocates objects in RAM and periodically cleans them up through garbage collection. On a server running for several hours, the heap fills up gradually.

When the heap reaches its maximum limit around midday (after hours of runtime since a morning restart), Java triggers a full garbage collection cycle. This freezes the entire server for 2 to 10 seconds. During that freeze, every player's connection times out.

How to test this:

• Check your server's console output for lines mentioning GC pauses
• Install the Spark profiler and run /spark gc to see garbage collection frequency and duration

How to fix it:

• Set your minimum and maximum RAM values to the same number: -Xms4G -Xmx4G (replace 4G with your allocation). This prevents the JVM from constantly resizing the heap
• Add the G1GC flags to your startup command:

-XX:+UseG1GC -XX:+ParallelRefProcEnabled -XX:MaxGCPauseMillis=200
-XX:+UnlockExperimentalVMOptions -XX:+DisableExplicitGC
-XX:G1NewSizePercent=30 -XX:G1MaxNewSizePercent=40
-XX:G1HeapRegionSize=8M -XX:G1ReservePercent=20
-XX:G1MixedGCCountTarget=4

These flags break garbage collection into many small pauses instead of one long freeze.

---

The Simplest Solution

If you are tired of diagnosing router tables and ISP throttling, the cleanest fix is to stop self-hosting entirely. A Minecraft server hosted on dedicated infrastructure runs on a static IP, with enterprise-grade routing, no NAT table, and no ISP interference.

Space-Node servers run on AMD Ryzen 9 3900X processors in the Netherlands with direct peering to European backbone networks. Your players connect to the datacenter, not to your home router. Time-based dropouts disappear because none of the four causes above apply to datacenter infrastructure.

Plans start at €0.90/month. Check the Minecraft hosting plans here.