192.168.1.4 is the fourth IP address in the range between 192.168.1.1 and 192.168.1.255. Home broadband routers often use this range when assigning addresses to local devices. A router can assign 192.168.1.4 to any device on the local network automatically, or an administrator can do it manually.
Automatic Assignment of 192.168.1.4
Computers and other devices that support dynamic address assignment using DHCP can obtain an IP address automatically from a router.
The router decides which address to assign from the range it is set up to manage (called the "DHCP pool").
For example, a router is set up with a local IP address of 192.168.1.1 normally maintains all of the addresses starting with 192.168.1.2 and ending with 192.168.1.255 in its DHCP pool. The router typically assign these pooled addresses in sequential order (although the order is not guaranteed). In this example, 192.168.1.4 is the third address in line (after 192.168.1.2 and 192.168.1.3) for allocation.
Manual Assignment of 192.168.1.4
Computers, phones, game consoles, printers, and some other kinds of devices allow setting an IP address manually. The text "192.168.1.4" or the four digits 192, 168, 1 and 4 must be keyed into an IP or Wi-Fi configuration screen on the device. However, simply entering the IP number does not guarantee the device can use it. The local network router must also have its subnet (network mask) configured to support 192.168.1.4.
See: Internet Protocol Tutorial - Subnets.
Issues with 192.168.1.4
Most networks assign private IP addresses using DHCP. Assigning 192.168.1.4 to a device manually (a process called "fixed" or "static" address assignment) is also possible but not recommended unless done by trained professionals.
IP address conflicts result when two devices on the same network are given the same address.
Many home network routers have 192.168.1.4 in their DHCP pool by default, and they do not check whether it has already been assigned to a client manually before assigning it to a client automatically. In the worst case, two different devices on the network will be assigned 192.168.1.4 - one manually and the other automatically - resulting in failed connection issues for both.
A device that was dynamically assigned IP address 192.168.1.4 may be re-assigned a different address if it is kept disconnected from the local network for a long enough time period. The length of time, called a lease period in DHCP, varies depending on the network configuration but is often 2 or 3 days. Even after the DHCP lease expires, a device is likely to still receive the same address the next time it joins the network unless other devices have also had their leases expire.