> ## Content Index > Fetch the complete content index at: https://snubmonkey.com/llms.txt > Use this file to discover other available public pages before exploring further. # Add Multiple IP Addresses into One Single Network Interface. (Server) - URL: https://snubmonkey.com/how-to-add-multiple-ip-addresses-into-one-single-network-interface/ - Published: 2023-10-24T06:06:19.000Z - Updated: 2025-04-16T22:31:04.000Z - Description: Adding an additional; secondary or third IP is a thing to think of when you are a Linux system administrator. Some of you may be curious as to why we would allocate numerous IP addresses to a single network card... - Author: Aleksandra Sloan - Tags: how to 🪄, linux 🐧 The first reason is just because you can ..., and yes Ubuntu server allows you to add multiple virtual IP addresses on a single network interface card without having to buy an additional network adapter. Let's take the scenario where you are testing a Linux system and need two or more network cards. Would you purchase a new one? ... .. . No, ...not necessary. You may configure a network card with various IP series, such as *192.168.1.4*, *192.168.2.2*, *192.168.3.12*, *etc.*, and utilize each of them simultaneously. Sounds helpful? – Of course, it is! ### **Permanently add an additional IP Address** Ubuntu uses the *Netplan utility* to configure networking. We will permanently add an additional IP address to our system by editing the file `/etc/netplan/50-cloud-init.yaml`. Let's find the IP address we are currently using: ``` $ ip addr 1: lo: mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: mtu 1500 qdisc mq state UP group default qlen 1000 link/ether xx:xx:32:xx:4x:x4 brd ff:ff:ff:ff:ff:ff inet 192.168.1.93/24 brd 192.168.1.255 scope global eth0 valid_lft forever preferred_lft forever inet6 xxzz::xxx:3xxf:fxx5:2xx7/64 scope link valid_lft forever preferred_lft forever 3: wlan0: mtu 1500 qdisc noop state DOWN group default qlen 1000 link/ether xx:xx:xx:xx:xx:xx brd ff:ff:ff:ff:ff:ff 4: tun0: mtu 1500 qdisc fq_codel state UNKNOWN group default qlen 500 link/none inet 10.8.0.1/24 scope global tun0 valid_lft forever preferred_lft forever inet6 fxxx::xxx:cxxx:xxxx:axxx/64 scope link stable-privacy valid_lft forever preferred_lft forever ``` As you see above, the IP address of my network card **eth0** is **192.168.1.19**. Now; what if we need to add another IP address, for example, **192.168.1.4**? Let's take a look at our current *Netplan configuration* and apply the change. ``` $ sudo cat 50-cloud-init.yaml [sudo] password for snubmonkey: # This is the network config written by 'subiquity' network: ethernets: eth0: dhcp4: no dhcp6: no addresses: - 192.168.1.93/24 - 192.168.1.4/24 <<< routes: - to: default via: 192.168.1.1 nameservers: addresses: - 9.9.9.9 search: - 208.67.222.222, 1.0.0.1 version: 2 ``` Here’s a brief explanation of each parameter: - **eth0**: A device name to be configured. - **dhcp4**: Used to enable or disable dhcp4. - **dhcp6**: Used to enable or disable dhcp6. - **addresses**: The IP address of the device. - **gateway4**: The IP address of your gateway. - **nameservers**: The IP address of your DNS server. Save and close the file when done. Enable the new configuration with the following command. ``` $ netplan apply ``` Restart the networking service. ``` $ sudo systemctl status systemd-networkd.service ``` Run the below command to check whether the new IP has been taken into account: ``` $ ip addr 1: lo: mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: mtu 1500 qdisc mq state UP group default qlen 1000 link/ether xx:xx:xx:xx:xx:ax brd ff:ff:ff:ff:ff:ff inet 192.168.1.93/24 brd 192.168.1.255 scope global eth0 valid_lft forever preferred_lft forever inet 192.168.1.4/24 brd 192.168.1.255 scope global secondary eth0 valid_lft forever preferred_lft forever inet6 fe80::xxxx:xxxx:fxx4:4xxx/64 scope link valid_lft forever preferred_lft forever 3: wlan0: mtu 1500 qdisc noop state DOWN group default qlen 1000 link/ether xc:x6:3x:x4:4x:xx brd ff:ff:ff:ff:ff:ff 4: tun0: mtu 1500 qdisc fq_codel state UNKNOWN group default qlen 500 link/none inet 10.8.0.1/24 scope global tun0 valid_lft forever preferred_lft forever inet6 fe80::xbxx:cxxx:x4xx:ax7x/64 scope link stable-privacy valid_lft forever preferred_lft forever2 ``` Let's double-check by pinging our new assignment address. `-a` : the system plays a sound when there is a response from a host. An audible ping is useful when you are troubleshooting network issues and do not want to look at the screen until there is a response. `-c` : automatically stops after it sends a certain number of packets, use **`-c` ,** and a number. This sets the desired amount of ping requests. *ps: as we may have noticed we used the `ip addr` in favor of the `ifconfig` command to view the network interface and IP address.* `ip addr` and `ip a` do the same. ### **BONUS** **Pros and cons of ip and ipconfig** Since it employs `Netlink` sockets rather than `ioctl` system calls, the `ip` command is more flexible and technically effective than the `ifconfig`. We will talk about this more in another of our *posts*; so stay tuned. Here is an example: ``` $ ifconfig eth0: flags=4163 mtu 1500 inet 192.168.1.93 netmask 255.255.255.0 broadcast 192.168.1.255 inet6 xxxx::xxxx:xxxx:xx1x:xxax prefixlen 64 scopeid 0x20 ether dc:a6:32:14:4e:a7 txqueuelen 1000 (Ethernet) RX packets 9713030 bytes 6030523854 (6.0 GB) RX errors 0 dropped 89 overruns 0 frame 0 TX packets 8998304 bytes 6420042303 (6.4 GB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 ... .. . ``` Have you spotted it? Using `ifconfig` command does not allow us to see whether or not our NIC is bound to multiple IP addresses.