Solved: dhcp server not pulling and unable to ping devices

mrescalante · ‎08-24-2023

I'm stuck on a review topology lab. I've done everything per the lab instructions and more but can't seem to get this going. attached the lab and the pkt in a zipped file.

Any feedback would be highly appreciated. Thanks

M02@rt37 · ‎08-25-2023

Hello @mrescalante,

Review the configuration of interfaces Gi0/1 - Gi0/2 on Switch S1 and Gi0/2 on Switch S2.

There are not in Trunk mode!

On S1:

interface giga 0/1
switchport mode trunk
no shut

idem to Gi 0/2

On S2:

interface giga 0/2
switchport mode trunk
no shut

After that DHCP is OK:

Do #show interface status on S1 and S2 to check the status and config ports. For example on S1 after Gi0/1 and 0/2 modifications:

Best regards
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Flavio Miranda · ‎08-25-2023

Hi @mrescalante

Interfaces between switches and between switches and router always in trunk mode.

Another point is that you have a DHCP scope on the DNS server and the DHCP service is enable. This can cause the devices to get wrong IP address. As your assignment ask only for DHCP on the router, you should disable it.

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M02@rt37 · ‎08-25-2023

@mrescalante,

On your router, look sub interface 0/0.99

Wrong mask!!! Put 255.255.255.0.

Thats why from pc vlan 20 you can not ping laptop 192.169.99.100.... this is out of /29 range!

Best regards
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M02@rt37 · ‎08-25-2023

@mrescalante,

You modify gig0/0 on Router?

Delete config under gi 0/0 and create sub interface gig 0/0.1 with this config:

encapsulation dot1q 1

ip add 192.168.1.1 255.255.255.0

No shut

Best regards
.ı|ı.ı|ı. If This Helps, Please Rate .ı|ı.ı|ı.

View solution in original post

M02@rt37 · ‎08-25-2023

Hello @mrescalante,

Review the configuration of interfaces Gi0/1 - Gi0/2 on Switch S1 and Gi0/2 on Switch S2.

There are not in Trunk mode!

On S1:

interface giga 0/1
switchport mode trunk
no shut

idem to Gi 0/2

On S2:

interface giga 0/2
switchport mode trunk
no shut

After that DHCP is OK:

Do #show interface status on S1 and S2 to check the status and config ports. For example on S1 after Gi0/1 and 0/2 modifications:

Best regards
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mrescalante · ‎08-25-2023

Thank you!!!!

M02@rt37 · ‎08-25-2023

You're welcome @mrescalante.

Best regards
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Flavio Miranda · ‎08-25-2023

Hi @mrescalante

Interfaces between switches and between switches and router always in trunk mode.

Another point is that you have a DHCP scope on the DNS server and the DHCP service is enable. This can cause the devices to get wrong IP address. As your assignment ask only for DHCP on the router, you should disable it.

mrescalante · ‎08-25-2023

I'll fix these - thanks so much!

M02@rt37 · ‎08-25-2023

@mrescalante,

On your router, look sub interface 0/0.99

Wrong mask!!! Put 255.255.255.0.

Thats why from pc vlan 20 you can not ping laptop 192.169.99.100.... this is out of /29 range!

Best regards
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mrescalante · ‎08-25-2023

Hi - can't send anymore private messages - reached the limit

ping to server 192.168.1.1 worked - thank you!!!

on S1

fa0/10 is server - accessing vlan 1

fa 0/24 is laptop - accessing vlan 99

think it's all good now

M02@rt37 · ‎08-25-2023

@mrescalante,

You modify gig0/0 on Router?

Delete config under gi 0/0 and create sub interface gig 0/0.1 with this config:

encapsulation dot1q 1

ip add 192.168.1.1 255.255.255.0

No shut

Best regards
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mrescalante · ‎08-25-2023

M02@rt37 · ‎08-25-2023

Perfect @mrescalante

Great news if it is OK now!

Best regards
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M02@rt37 · ‎08-25-2023

@mrescalante

Please find here articles about Router on a Stick.

https://www.ciscopress.com/articles/article.asp?p=3089357&seqNum=5

Best regards
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