Running a VPS means managing network configuration. Here's what every VPS owner needs to know about DNS, ports, and IP addresses.
IP Addresses
IPv4 vs IPv6
| Feature | IPv4 | IPv6 | |---------|------|------| | Format | 185.xxx.xxx.xxx | 2a0a:xxxx:xxxx::1 | | Addresses available | Limited (running out) | Virtually unlimited | | NAT required | Often | Never | | Configuration | Standard | Growing adoption |
Most VPS providers assign at least one IPv4 and one IPv6 address.
Check Your IPs
# IPv4
curl -4 ifconfig.me
# IPv6
curl -6 ifconfig.me
# All network interfaces
ip addr show
DNS Management
Record Types
| Record | Purpose | Example | |--------|---------|---------| | A | Points domain to IPv4 | example.com -> 185.x.x.x | | AAAA | Points domain to IPv6 | example.com -> 2a0a::1 | | CNAME | Alias to another domain | www -> example.com | | MX | Mail server | mail.example.com | | TXT | Text data (SPF, DKIM, verification) | v=spf1 include:... | | NS | Nameserver | ns1.provider.com | | SRV | Service location | Specific service endpoints |
Setting Up DNS for Your VPS
- Buy a domain from a registrar
- Point the domain's A record to your VPS IP
- Wait for propagation (usually 5-30 minutes, up to 48 hours)
example.com A 185.xxx.xxx.xxx
www.example.com CNAME example.com
Verify DNS
# Check A record
dig example.com A +short
# Check all records
dig example.com ANY
# Check propagation worldwide
dig @8.8.8.8 example.com
dig @1.1.1.1 example.com
Port Management
Common Ports
| Port | Service | Protocol | |------|---------|----------| | 22 | SSH | TCP | | 80 | HTTP | TCP | | 443 | HTTPS | TCP | | 25 | SMTP | TCP | | 3306 | MySQL | TCP | | 5432 | PostgreSQL | TCP | | 6379 | Redis | TCP | | 8080 | HTTP alternate | TCP |
Firewall Rules
# See current rules
sudo ufw status verbose
# Allow a port
sudo ufw allow 3000/tcp
# Allow from specific IP only
sudo ufw allow from 192.168.1.100 to any port 3306
# Deny a port
sudo ufw deny 8080/tcp
# Delete a rule
sudo ufw delete allow 3000/tcp
Only Expose What's Needed
| Service | Should Be Public? | Firewall Rule | |---------|-------------------|--------------| | Web server (80, 443) | Yes | Allow from anywhere | | SSH | Yes (restricted) | Allow from your IP or all | | Database | No | Allow from localhost only | | Redis | No | Allow from localhost only | | Admin panels | No | Allow from your IP only |
Binding to Localhost
For services that shouldn't be public:
# MySQL - bind to localhost only
# /etc/mysql/mariadb.conf.d/50-server.cnf
bind-address = 127.0.0.1
# Redis - bind to localhost only
# /etc/redis/redis.conf
bind 127.0.0.1
Reverse DNS (rDNS)
Reverse DNS maps an IP address back to a domain name. Essential for email:
- Without rDNS: Email servers reject your emails as potential spam
- With rDNS: Your VPS IP resolves to your domain, improving email deliverability
Set up rDNS through your VPS provider's control panel.
HTTPS with Let's Encrypt
sudo apt install certbot
# For Nginx
sudo certbot --nginx -d example.com -d www.example.com
# For Apache
sudo certbot --apache -d example.com -d www.example.com
Certbot automatically handles renewal.
Network Performance
| Test | Command |
|------|---------|
| Download speed | wget -O /dev/null http://speedtest.tele2.net/10MB.zip |
| Latency | ping -c 10 google.com |
| Traceroute | traceroute google.com |
| DNS resolution speed | dig google.com \| grep "Query time" |
Space-Node's VPS hosting connects directly to major internet exchanges with 1 Gbps connectivity. Low latency to all European networks and excellent global routing.
