To connect to your server, you’ll need your server IP address, username, and password. You can find the IP address and username in the email titled “Your login data!”. Please be aware that we do not store your password, so you need to keep it safe after setting it during the order process.

The connection method depends on your server’s operating system:

• Linux servers: connect using SSH
• Windows servers: connect using Remote Desktop (RDP)

For step-by-step instructions, please see How do I connect to my Contabo server for the first time?

Having trouble connecting?
Try the following:

• Check the Contabo Server Status page for outages
• Restart your server via the Customer Control Panel
• Access your server via VNC
• Use the “Can’t reach server” form

For detailed troubleshooting steps, see the full article:I can't connect to my server, what do I do?

You can reset your server password anytime via the Customer Panel.

For Linux servers:
The password reset feature allows you to set a new password for the root user. Simply open your server in the Control Panel and select “Reset credentials”.

Important:

• This feature works only for Linux servers (root user)
• It does not work for Windows servers

For Windows servers:
Due to security restrictions, the Administrator password cannot be reset. If you’ve lost access, please refer to please refer to our blog article on how to recover your files in that scenario.

You can check your order status anytime on the Order Status page.

Just enter your email address (used during purchase), and your Order ID (from your confirmation email).  You’ll see real-time updates on your order.

Note:

• You’ll receive your login details via email once the server is ready (“Your login data!”)
• If your order shows “Verification Needed”, follow the instructions in the email to proceed

For more details, see the full guide.

You can cancel your service anytime via the Customer Panel.

• Go to your service (VPS, VDS, or Dedicated Server)
• Select “Cancel” from the options
• Confirm the cancellation

Your service will remain active until the displayed cancellation date.

Important:

• Make sure to back up your data before the service ends. Cancelling a VPS permanently deletes all associated snapshots and backups. This cannot be reversed. 
• Your account will be automatically closed once all services are canceled

For full steps and options (e.g. revoking a cancellation), see the full guide.

You may be eligible for a refund in one of the following situations:

Within 14 days of purchase (revocation period)
This is a formal revocation - no separate cancellation is needed. Contact Customer Support within 14 days to request it. Note: revocation is only available to private accounts; domains are excluded.

A renewal payment made within the last 72 hours
Retroactive cancellation of an already-renewed service cannot be handled through the Customer Control Panel. Please contact customer support directly - this requires manual handling by the support team.

An accidental recent order
Contact Customer Support as soon as possible.

To request a refund, please contact support.

Important:

• Refunds are issued to the original payment method
• Requests outside these conditions may not be eligible

For full details and step-by-step instructions, see the full guide.

In most cases, this is a temporary preauthorization, not an actual charge.

We place a small hold on your payment method a few days before the due date to verify funds. This may appear as a pending transaction, but:

• It is not a final charge
• It will either be completed on the due date or automatically released by your bank

Common situations:

• Before renewal: A temporary hold is placed in advance
• After cancellation: A hold may still appear but will be released if cancellation was completed in time
• With account balance: A hold may still be placed, even if your balance covers the payment

If you believe your payment information was used fraudulently

If you don't recognize a charge and suspect unauthorized use of your payment method, please contact your bank or card issuer directly as soon as possible. They are best equipped to investigate the matter and will reach out to us if any action is required on our end. If you have further questions after speaking with your payment provider, feel free to contact support.

This article helps you identify and resolve unstable server connection issues. Follow the diagnostic steps for the category that best matches your symptoms.

1. Local / Client-Side Issues

Connection problems sometimes originate on your end. Check the following before investigating the server.

Local Network Issues

1. Restart your router and modem, then wait 60 seconds before reconnecting.
2. Test your internet connection by visiting a reliable website or running a speed test.
3. Try connecting from a different network (e.g. mobile hotspot) to rule out your local network as the cause.
4. If you are on Wi-Fi, switch to a wired connection to eliminate wireless interference.

VPN or Firewall Interference

1. Temporarily disable any active VPN and attempt to reconnect to the server.
2. Check your local firewall or security software to ensure it is not blocking the connection port.
3. If using a corporate firewall, contact your network administrator to verify outbound traffic is permitted.

DNS Resolution Issues

1. Try connecting to your server using its IP address directly instead of the hostname to bypass DNS.
2. Flush your local DNS cache:

• Windows: ipconfig /flushdns
• macOS: sudo dscacheutil -flushcache
• Linux: sudo systemd-resolve --flush-caches

3. Switch to a public DNS resolver such as 1.1.1.1 (Cloudflare) or 8.8.8.8 (Google) and test again.

2. Network Path / Routing Issues

Packet loss between your machine and the server can cause intermittent drops or high latency.

Packet Loss Along the Route

1. Run a traceroute or MTR to your server to identify where in the network path loss is occurring (see Section 6 – Diagnostic Tools).
2. Share the output with Contabo Support so we can investigate the affected network segment.

Issue on Contabo’s Side

1. Check the Contabo Status Page for any active incidents or maintenance affecting your region.
2. If an incident is listed, monitor the status page for updates. No further action is required on your end.
3. If no incident is listed but you suspect a routing problem on our infrastructure, contact Contabo Support with your traceroute/MTR results.

3. Server Network Configuration

Misconfigured settings on the server itself can cause connections to be dropped or refused.

Incorrect Network Interface Settings

1. Log in via the Contabo VNC/KVM console — this requires an external VNC client (e.g. RealVNC, TigerVNC) connected to the VNC credentials provided in the Customer Control Panel, not a panel-embedded console — as this method bypasses the server's network entirely. Once connected, verify the network interface is up: ip link show 
2. Confirm the correct IP address, subnet mask, and gateway are configured: ip addr show and ip route show
3. Restart the networking service if settings appear correct but the interface is down: sudo systemctl restart networking (Debian/Ubuntu) or sudo systemctl restart NetworkManager (CentOS/RHEL).

Firewall Rules Dropping Packets

1. Review your firewall rules to ensure the required ports are not inadvertently blocked: sudo iptables -L -n -v or sudo ufw status verbose
2. Temporarily flush rules in a test environment to confirm the firewall is the cause: sudo iptables -F (use with caution – this removes all rules).
3. Re-add only the necessary rules and verify connectivity after each change.

NIC Issues or Driver Problems

1. Check kernel logs for NIC errors: sudo dmesg | grep -i eth or sudo journalctl -k | grep -i net
2. If driver errors appear, contact Contabo Support – NIC-level issues on virtual or dedicated servers require our intervention.

4. DDoS or Traffic Flooding

A DDoS attack or unexpected traffic surge can overwhelm your server and cause connection instability.

1. Check your server’s incoming traffic metrics in the Contabo Customer Control Panel to identify unusual spikes.
2. Inspect active connections: ss -nt | awk '{print $5}' | cut -d: -f1 | sort | uniq -c | sort -rn | head -20
3. If a DDoS attack is confirmed or suspected, contact Contabo Support immediately. We can apply network-level mitigation measures.
4. As a short-term measure, consider implementing rate limiting or blocking the offending IP ranges using your firewall.

5. Resource Exhaustion Affecting Network

High CPU or RAM usage can cause the server’s network stack to become unresponsive, resulting in connection timeouts.

CPU / RAM Overload

1. Check current resource usage: top or htop
2. Identify and stop any runaway processes consuming excessive CPU or memory.
3. If the server itself is consistently within normal limits but timeouts persist, the host node may be overloaded.

⚠️  Note: Host node overload cannot be resolved by the customer. Please contact Contabo Support so we can assess the situation and migrate your server to a less loaded host if necessary.

Network Bandwidth Overload

1. Monitor current bandwidth usage: vnstat -i eth0 -l or nload eth0
2. Identify processes generating the most traffic: nethogs or iftop
3. Throttle or stop high-bandwidth processes where possible.
4. If you are regularly hitting your bandwidth limit, consider upgrading your plan or reviewing application traffic patterns.

See How to reduce outgoing traffic for more information.

6. Diagnostic Tools

The following tools help pinpoint where a connection issue originates. For a full diagnostics guide, see How can I run diagnostics on my server?.

traceroute / tracert

Shows each hop between your machine and the server, and reports latency and packet loss per hop. Use this to narrow down which network segment is causing problems.

• Linux / macOS: traceroute <server-ip>
• Windows: tracert <server-ip>

MTR 

Combines the functions of traceroute and ping into a continuously updated report. Provides more reliable data on intermittent packet loss.

• Linux: mtr <server-ip> (install via sudo apt install mtr or sudo yum install mtr)
• Windows: WinMTR (GUI application, available at winmtr.net)
• Run for at least 60 seconds and save the output before contacting support.

Still Having Issues?

If you have worked through the steps above and the problem persists, please contact Contabo Support and include:

• Your server IP address and hostname
• A description of the symptoms and when they started
• Output from traceroute / MTR
• Any relevant log entries or error messages

This helps our team diagnose the issue faster and provide an accurate resolution.