IP Addresses are pretty common around the internet so they're often easily found in plain text. However, let's say there's a number of IP addresses configured on a server to allow access through a firewall to specific locations. So, 1) these addresses are allowed access to a protected server and 2) someone else owns these IP addresses.
Is it "safe" to send a list of IP addresses to the owner or another trusted entity in plain text? Possibly via email? If not, what is the bare minimum solution that would be "good enough" considering limited resources that I may or may not have?