Transparent proxy ip range is not configurable

[dzarpelon]

Feature Description

No Configuration Parameters: A review of Consul's service definition schema and configuration options shows no parameters for customizing the virtual IP range.

Hardcoded Implementation in Source Code: The virtual IP range is hardcoded in Consul's source code at:

File: agent/consul/state/catalog.go (lines 43-45)

var (
	// startingVirtualIP is the start of the virtual IP range we assign to services.
	// The effective CIDR range is startingVirtualIP to (startingVirtualIP + virtualIPMaxOffset).
	startingVirtualIP = net.IP{240, 0, 0, 0}

	virtualIPMaxOffset = net.IP{15, 255, 255, 254}
)

This shows that:

• Starting IP: 240.0.0.0 (hardcoded as net.IP{240, 0, 0, 0})
• Maximum offset: 15.255.255.254 (defining the upper bound)
• Effective range: 240.0.0.0 to 255.255.255.254 (the entire 240.0.0.0/4 block)

File: agent/consul/state/catalog.go (functions using these constants)

• assignServiceVirtualIP() - Assigns virtual IPs to services
• addIPOffset() - Performs IP arithmetic within the range
• ServiceVirtualIP.IPWithOffset() - Calculates final IP addresses

Use Case(s)

This ip range can be in use by other services which can cause possible ip duplication and network instabilities.