My hosted server answers to requests it's not the target for

I am having a problem with a hosted server. It answers to requests to IP 4.9.81.102 but it's IP is 4.8.81.114

This only happens when "real" 4.9.81.102 is offline. I guess it might happen when the "real" server is offline and my hosts routers send ARP broadcasts.

I am running Debian and don't know how to disable this behaviour. I don't even know why it's happening. Any ideas?

My Interface: 4.8.81.114 10:BF:48:7F:E6:7E

Request to 4.8.81.102 (my server answers it)

08:14:37.711042 10:bf:48:7f:e6:7e > f8:c0:01:cf:5a:a6, ethertype IPv4 (0x0800), length 74: 4.8.81.102.80 > 188.40.25.34.38620: Flags [S.], seq 2676656877, ack 707376748, win 28960, options [mss 1460,sackOK,TS val 270682405 ecr 402214897,nop,wscale 7], length 0 08:14:37.711048 10:bf:48:7f:e6:7e > f8:c0:01:cf:5a:a6, ethertype IPv4 (0x0800), length 74: 4.8.81.102.443 > 188.40.25.34.37957: Flags [S.], seq 2420082922, ack 3076168719, win 28960, options [mss 1460,sackOK,TS val 270682405 ecr 402214897,nop,wscale 7], length 0