Default Port Restrictions on Linux VPS

title: Default Port Restrictions on Linux VPS created at: Fri May 16 2025 16:56:00 GMT+0000 (Coordinated Universal Time) updated at: Fri May 16 2025 17:17:45 GMT+0000 (Coordinated Universal Time) --- # Default Port Restrictions on Linux VPS At **Illevante Cloud**, we prioritize the **security, stability, and integrity** of our network and clients. To prevent abuse, protect your data, and ensure fair resource usage, certain **network ports are restricted by default** on all **Linux-based virtual machines** (VPS) hosted on our platform. This article outlines the **incoming and outgoing ports that are blocked** and explains **why** these restrictions are in place. # Why Are Ports Restricted? Many ports are commonly targeted for: * Spam delivery (SMTP abuse) * DDoS amplification * Botnet command-and-control channels * Vulnerabilities in outdated or misconfigured services Restricting access to these ports by default: * Prevents malicious activity * Reduces the risk of server compromise * Ensures better performance across the node # Restricted Incoming Ports These ports are **blocked inbound** by default unless you explicitly request access and apply proper security controls. | Port(s) | Protocol | Description | | ---------- | -------- | -------------------------------------------- | | 23 | TCP | Telnet – insecure remote shell | | 69 | UDP | TFTP – trivial file transfer, easily abused | | 5060 | UDP/TCP | SIP – VoIP protocol targeted by scanners | | 520 | UDP | RIP – legacy routing protocol | | 6660–6669 | TCP | IRC – used in botnet and C2 activity | | 11211 | TCP/UDP | Memcached – vulnerable to DDoS amplification | | 161–162 | UDP | SNMP – reflection/amplification vector | | 1900 | UDP | SSDP – often used in UPnP exploits | | 3306 | TCP | MySQL – exposed databases are at risk | | 5432 | TCP | PostgreSQL – restrict to private access only | | 8080, 8443 | TCP | Alternative web ports – often attacked | | 10000 | TCP | Webmin – remote admin interface | > \[!NOTE] > If you need one of these ports opened, contact our [**support team**](https://my.illevante.com/billmgr?startform=clientticket) . We recommend strict firewall rules and authentication before exposing any administrative or sensitive service. # Restricted Outgoing Ports These ports are **blocked outbound** to prevent abuse from within VMs, particularly for email spam or reflection attacks. | Port(s) | Protocol | Description | | --------- | -------- | ------------------------------------------- | | 25 | TCP | SMTP – blocked to prevent spam | | 465, 587 | TCP | Encrypted SMTP – restricted, use mail relay | | 69 | UDP | TFTP – outbound file transfers blocked | | 123 | UDP | NTP – limits DDoS amplification attacks | | 1900 | UDP | SSDP – blocks outbound UPnP abuse | | 11211 | TCP/UDP | Memcached – outbound DDoS prevention | | 6660–6669 | TCP | IRC – blocks botnet communication | | 17 | UDP | QOTD – used in some DDoS attack methods | # What Ports Are Open? By default, the following ports are **open** and commonly used for normal operation: | Port | Service | Use Case | | ---- | ------- | ------------------------ | | 22 | SSH | Secure remote login | | 80 | HTTP | Websites and apps | | 443 | HTTPS | Secure websites and APIs | | 53 | DNS | Outbound name resolution | You can also open additional ports through your firewall (e.g. `ufw`, `firewalld`, `iptables`) or request assistance from our [**support team**](https://my.illevante.com/billmgr?startform=clientticket) . # Best Practices * **Use a firewall**: Configure `ufw`, `iptables`, or `firewalld` to control open ports. * **Enable key-based SSH login**: Avoid password authentication for better security. * **Use secure mail relays**: To send email from your VPS, use Illevante Cloud’s outbound relay or SMTP relay service or a third-party SMTP provider like Mailgun, SendGrid. * **Expose databases only internally**: Use private networking or restrict to trusted IPs. # Need a Specific Port Open? If your application requires access to a restricted port (e.g. VoIP, outbound SMTP), please [**contact support**](https://my.illevante.com/billmgr?startform=clientticket) with the following details: * Purpose of the port * Security measures in place (e.g., firewall, authentication) * Destination or source IPs (if applicable) We'll review your request and enable access if it complies with our security and abuse policies.