A "problem" with a quiz question on Gilmore...

[Tracy_Baker]

(This is a copy of an email I'm sending Lauren - I'm assuming she might not know networking. That's why it is worded the way it is...)

On Gilmore there is a "problem" with a quiz question. It is for the RHEL 8 material, RH124 course, chapter 12, section 2:

However, they forgot to include some very important information - something called a netmask (or CIDR or subnet mask). Without it, there are three possible correct answers. There is one that is always incorrect (the one with 256 - a number that isn't allowed in IPv4 networking).

They are assuming that an IPv4 address beginning with 192 automatically uses a netmask of /24 (with this assumption, there is only one correct answer). It does not. Many (most) colleges that are RHAs are also Cisco Academies, so the students are taught that other netmasks can be, and often are, used. See my example, below, where I used a /23 and all three adresses (.188, .0, .255) worked just fine.

I'm not suggesting that RH teach Cisco-level networking. I am suggesting that this question include the /24, with each address that is listed, to make it clearly correct.

[root@server63 ~]# nmcli con add con-name testif type ethernet autoconnect no ifname ens39 ip4 192.168.1.188/23
Connection 'testif' (47c34f55-7e0e-4567-b3d8-9aaa25a5c254) successfully added.
[root@server63 ~]# nmcli con up testif 
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/6)
[root@server63 ~]# ping -c1 192.168.1.188
PING 192.168.1.188 (192.168.1.188) 56(84) bytes of data.
64 bytes from 192.168.1.188: icmp_seq=1 ttl=64 time=0.035 ms

--- 192.168.1.188 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.035/0.035/0.035/0.000 ms

[root@server63 ~]# nmcli con mod testif ipv4.addresses 192.168.1.255/23
[root@server63 ~]# nmcli con down testif && nmcli con up testif 
Connection 'testif' successfully deactivated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/6)
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/7)
[root@server63 ~]# ping -c1 192.168.1.255
PING 192.168.1.255 (192.168.1.255) 56(84) bytes of data.
64 bytes from 192.168.1.255: icmp_seq=1 ttl=64 time=0.035 ms

--- 192.168.1.255 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.035/0.035/0.035/0.000 ms

[root@server63 ~]# nmcli con mod testif ipv4.addresses 192.168.1.0/23
[root@server63 ~]# nmcli con down testif && nmcli con up testif 
Connection 'testif' successfully deactivated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/7)
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/8)
[root@server63 ~]# ping -c1 192.168.1.0
PING 192.168.1.0 (192.168.1.0) 56(84) bytes of data.
64 bytes from 192.168.1.0: icmp_seq=1 ttl=64 time=0.035 ms

--- 192.168.1.0 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.035/0.035/0.035/0.000 ms

[Ashish_Lingayat]

Hi @Tracy_Baker ,

Thank you for bringing this to our notice.

I have forwarded this to curriculum team through internal channels so that they can look into it and take appropiate actions.

Thank you for your efforts in making our courses better.

Happy learning!

Regards,

Ashish Lingayat