The provided netmask, 255.255.255.223, is invalid according to standard IP networking principles. A valid netmask, in its 32-bit binary form, must contain a contiguous sequence of ones followed by a contiguous sequence of zeros. The binary representation of the final octet, 223, is 11011111, which violates this rule. The most common and logical correction, given a typical management network setup and the gateway 10.24.18.1, is to assume a standard /24 network. Changing the netmask to 255.255.255.0 (a /24 mask) resolves the invalidity and creates a standard, functional IP configuration where the gateway is valid for the subnet.

A. Changing the gateway address does not resolve the primary issue, which is that the netmask 255.255.255.223 is fundamentally invalid and will be rejected.

C. While /23 (255.255.254.0) is a valid netmask, it is a less probable correction. The error is in the last octet, making a change to 255.255.255.0 a more direct and common fix.

1. Pure Storage FlashArray Installation and Upgrade Guide (Doc. 30-001-0106 Rev L): In the "Site Planning and Network Configuration Worksheet" section, customers are required to provide a valid Subnet Mask for each management port. This implies adherence to universal networking standards for the configuration to be accepted by the system. The provided value is not a valid subnet mask.

2. RFC 950, Internet Standard Subnetting Procedure, Section 2.1: This foundational document defines the structure of a subnet mask. It states, "The subnet field is of variable length, and is specified by a bit-mask... This mask is a 32-bit number with a block of 1s on the left and a block of 0s on the right." The binary value of 223 (11011111) violates this requirement.

3. Dordal, P. L. (2019). An Introduction to Computer Networks. Chapter 9.2, The Subnet Mask. This university-level text explains that the subnet mask's purpose is to separate the network part of an address from the host part. It reinforces that this is achieved by a mask with a contiguous block of network bits (1s) followed by host bits (0s).