Additional IP addresses and IPv6: ordering and configuring them

Every UnderHost Cloud VPS and most dedicated servers include at least one dedicated IPv4 address. You can add more when a project needs them, and IPv6 is included or available on request depending on the server. Some dedicated servers include more: for example, the Tesla T4 GPU server comes with 5 IPv4 addresses, and gaming servers with 2.

Extra IPv4 prices

Each product page lists what is included and the IP options for that server and location. Some specialised servers include no additional IPs, so check before you order.

Justification and IP policy

IPv4 addresses are scarce and are managed under the policies of the regional internet registries (RIPE NCC in Europe, ARIN in North America). So:

• Additional IPv4 addresses may require justification, and are subject to availability at each location.
• Requests for larger blocks go to the sales team, and justification may be required for approval.
• UnderHost may deny, reduce, reclaim, renumber or require justification for IP allocations, including IPs requested for SEO, mailing, network segmentation, SSL, nameservers, virtualization or separating applications. See the Acceptable Use Policy.

A good justification says what each address is for: for example, "two IPs for two customer VPS containers" or "one IP per isolated client application". Modern TLS (SNI) lets many HTTPS sites share one IP, so a separate IP per website is rarely needed.

How to order

1. At checkout

   Choose the number of additional IPs in the server's configuration options when you order. Cloud VPS orders allow up to 2 extra at checkout.

2. On an existing server

   Open a ticket in @CustomerPanel with the server, the number of IPs and what they are for.

3. For a block

   Contact sales with your requirements. A /24 block is available on some dedicated servers.

When the IPs are assigned, you receive each address with its netmask and gateway.

IPv6

Depending on the server, IPv6 is either included, often as a /64 subnet, or available on request. A /64 contains far more addresses than you will ever need, so one subnet is enough for any number of sites and containers on the server. Ask support to enable IPv6 if your server shows no IPv6 address.

Add an IP on Linux

First check whether the address is already configured: ip -br addr. If not, add it. In the examples, 203.0.113.20/24 is the new address with its prefix; use the values you received.

# /etc/netplan/50-cloud-init.yaml (your file name may differ): add the address under the interface
network:
  version: 2
  ethernets:
    eth0:
      addresses:
        - 203.0.113.10/24      # existing address
        - 203.0.113.20/24      # new address
        - 2001:db8:1234::10/64 # IPv6, if assigned

# test with automatic rollback, then apply
netplan try
netplan apply

nmcli con show                                   # find the connection name
nmcli con mod "System eth0" +ipv4.addresses 203.0.113.20/24
nmcli con up "System eth0"

auto eth0:1
iface eth0:1 inet static
    address 203.0.113.20/24

# then bring it up
ifup eth0:1

Add an IP on Windows Server

Get-NetIPAddress -AddressFamily IPv4 | Format-Table InterfaceAlias, IPAddress, PrefixLength
New-NetIPAddress -InterfaceAlias "Ethernet" -IPAddress 203.0.113.20 -PrefixLength 24

Or open Network Connections → adapter Properties → Internet Protocol Version 4 → Advanced and add the address. Do not change the existing address or gateway.

After adding an IP

• Test it from outside: ping 203.0.113.20, or connect to a service bound to it.
• Bind your services (web server, mail, applications) to the new address where needed.
• Set reverse DNS if the address sends mail. See Set reverse DNS.
• Remove IPs you no longer use to save their monthly cost. See Keep server costs under control.

FAQ

Related: Set reverse DNS | Linux server basics | Windows VPS and RDP | Keep costs under control

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