How to add IP address to iproute2 table from IP block?

Question

CentOS

Good afternoon. Can you please tell me why I cannot add an IP address to the iproute2 table from the IP block?

There is a block of four IP addresses: xxx.xxx.xxx.60-xxx.xxx.xxx.63. I enter the first four addresses in the table without problems:

ip route add xxx.xxx.xxx.60 dev ens20 scope link src xxx.xxx.xxx.60 table wan-60
ip route add xxx.xxx.xxx.61 dev ens21 scope link src xxx.xxx.xxx.61 table wan -61
ip route add xxx.xxx.xxx.62 dev ens22 scope link src xxx.xxx.xxx.62 table wan-62
Here's the last one, I get:
ip route add xxx.xxx.xxx.63 dev ens23 scope link src xxx.xxx.xxx.63 table wan-63
Error: Invalid prefsrc address.

I so guess that the last is ala the gateway. But, the mask for this block is /30 (255.255.255.252). That is, in fact, the gateway is xxx.xxx.xxx.252. I just can't get the logic. Please advise



Thank you!

Answer 1

Judging by your phrase "That is, in fact, the gateway is xxx.xxx.xxx.252" you do not understand what a subnet mask is.
You have a subnet of 4 addresses (just the same mask 255.255.255.252), of which two are available to you - the second and third.
The first address is the network ID.
The last address on the subnet is the reserved address for broadcasts.