1

I have a question regarding my network; can anyone tell me if this is a problem or not?

When giving the command arp -a in the terminal, I see all my connected devices, but there are a bunch of IP addresses that have a different IP numbers and I don't recognize them.

See my log:

Mac-mini-2018-van-Richard:~ richard$ arp -a
? (192.168.1.1) at 90:72:40:9:37:e on en0 ifscope [ethernet]
? (192.168.1.2) at b8:ec:a3:21:d0:37 on en0 ifscope [ethernet]
? (192.168.1.3) at 74:a:bc:10:4b:7c on en0 ifscope [ethernet]
? (192.168.1.4) at d8:49:2f:23:79:13 on en0 ifscope [ethernet]
? (192.168.1.5) at 84:c0:ef:c0:2b:4e on en0 ifscope [ethernet]
? (192.168.1.6) at bc:99:11:94:b4:98 on en0 ifscope [ethernet]
? (192.168.1.7) at 18:b4:30:d2:a4:f1 on en0 ifscope [ethernet]
? (192.168.1.9) at e0:33:8e:d1:94:34 on en0 ifscope [ethernet]
? (192.168.1.10) at 0:6:78:32:14:25 on en0 ifscope [ethernet]
? (192.168.1.12) at 48:d7:5:ef:41:c2 on en0 ifscope [ethernet]
? (192.168.1.23) at 5c:f4:ab:63:e3:30 on en0 ifscope [ethernet]
? (192.168.1.27) at f8:46:1c:a0:58:19 on en0 ifscope [ethernet]
? (192.168.1.29) at 40:cb:c0:ac:3d:fb on en0 ifscope [ethernet]
? (192.168.1.44) at f0:18:98:e8:6d:6 on en0 ifscope permanent [ethernet]
? (192.168.1.52) at dc:a6:32:6f:ad:72 on en0 ifscope [ethernet]
? (192.168.1.55) at 0:6:78:20:a:9f on en0 ifscope [ethernet]
? (192.168.1.56) at 50:de:6:9a:7f:19 on en0 ifscope [ethernet]
? (192.168.1.59) at 3c:6a:9d:14:38:6d on en0 ifscope [ethernet]
? (192.168.1.255) at ff:ff:ff:ff:ff:ff on en0 ifscope [ethernet]
all-systems.mcast.net (224.0.0.1) at 1:0:5e:0:0:1 on en0 ifscope permanent [ethernet]
? (224.0.0.251) at 1:0:5e:0:0:fb on en0 ifscope permanent [ethernet]
? (225.11.89.110) at 1:0:5e:b:59:6e on en0 ifscope permanent [ethernet]
? (225.255.255.255) at 1:0:5e:7f:ff:ff on en0 ifscope permanent [ethernet]
? (227.72.38.171) at 1:0:5e:48:26:ab on en0 ifscope permanent [ethernet]
? (230.128.242.42) at 1:0:5e:0:f2:2a on en0 ifscope permanent [ethernet]
? (230.226.118.14) at 1:0:5e:62:76:e on en0 ifscope permanent [ethernet]
? (232.140.250.183) at 1:0:5e:c:fa:b7 on en0 ifscope permanent [ethernet]
? (234.51.79.222) at 1:0:5e:33:4f:de on en0 ifscope permanent [ethernet]
? (236.85.84.112) at 1:0:5e:55:54:70 on en0 ifscope permanent [ethernet]
? (236.202.5.112) at 1:0:5e:4a:5:70 on en0 ifscope permanent [ethernet]
? (237.30.215.60) at 1:0:5e:1e:d7:3c on en0 ifscope permanent [ethernet]
? (239.140.109.112) at 1:0:5e:c:6d:70 on en0 ifscope permanent [ethernet]
? (239.255.255.250) at 1:0:5e:7f:ff:fa on en0 ifscope permanent [ethernet]
? (239.255.255.250) at 1:0:5e:7f:ff:fa on en1 ifscope permanent [ethernet]
broadcasthost (255.255.255.255) at ff:ff:ff:ff:ff:ff on en0 ifscope [ethernet]

Can anyone tell my if the IP numbers starting with 2 are okay or can they be harmful?

2

Those IP’s are fine.

  • the 225 address are usually broadcast addresses (Class E)
  • Three are Class D IPs and is reserved for Multicast. They're not even valid IPs for network nodes.

They are perfectly safe and pose no threat.

2
  • Thank you for clarifying!
    – Restart
    Aug 5 '20 at 10:53
  • No worries. If you want to have some fun and find all the devices on your network ping the broadcast address. Normally, it's the last IP address (192.168.1.255 in your case). But, if you're not sure, just issue the command ifconfig en0 | grep broadcast Then ping it. Every device on your device that's live will respond (you will get dupes).
    – Allan
    Aug 5 '20 at 11:00

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