Re: Expanding network with new subnet range

BeckyBoo123 · ‎08-05-2021

Hi all...again!

I have another question which I think is an easy one but I have not come across this yet in my short lived network career.

We have an existing network 10.11.0.0/16 which we use for data. I am trying to add a new network 10.12.60.0/24 to trial a sperate voice network.

Any handset on the 10.11.60.0/24 will need to still access DHCP on 10.11.202.1.

I have a test device with a static IP address (10.12.60.254) currently for testing but that cannot see the local network either.

I have added additional routes and EIGRP entries to our core switch but the rest of the network is not learning. Am I missing something?

router eigrp 11
 network 10.11.0.247 0.0.0.0
 network 10.11.1.247 0.0.0.0
 network 10.11.2.0 0.0.0.255
 network 10.11.3.0 0.0.0.255
 network 10.11.4.0 0.0.0.255
 network 10.11.4.247 0.0.0.0
 network 10.11.5.247 0.0.0.0
 network 10.11.7.247 0.0.0.0
 network 10.11.9.247 0.0.0.0
 network 10.11.18.0 0.0.0.255
 network 10.11.21.1 0.0.0.0
 network 10.11.22.247 0.0.0.0
 network 10.11.23.0 0.0.0.255
 network 10.11.23.247 0.0.0.0
 network 10.11.60.0 0.0.0.255
 network 10.11.101.0 0.0.0.255
 network 10.11.102.0 0.0.0.255
 network 10.11.103.0 0.0.0.255
 network 10.11.104.0 0.0.0.255
 network 10.11.105.0 0.0.0.255
 network 10.11.106.0 0.0.0.255
 network 10.11.107.0 0.0.0.255
 network 10.11.108.0 0.0.0.255
 network 10.11.109.0 0.0.0.255
 network 10.11.110.0 0.0.0.255
 network 10.11.111.0 0.0.0.255
 network 10.11.112.0 0.0.0.255
 network 10.11.113.0 0.0.0.255
 network 10.11.114.0 0.0.0.255
 network 10.11.115.0 0.0.0.255
 network 10.11.116.0 0.0.0.255
 network 10.11.117.0 0.0.0.255
 network 10.11.118.0 0.0.0.255
 network 10.11.119.0 0.0.0.255
 network 10.11.120.0 0.0.0.255
 network 10.11.210.0 0.0.0.255
 network 10.11.211.0 0.0.0.255
 network 10.12.60.0 0.0.0.255
 network 10.20.1.0 0.0.0.255
 network 10.21.0.0 0.0.255.255
 network 10.30.0.0 0.0.255.255
 network 10.40.0.0 0.0.255.255
 network 10.50.0.0 0.0.255.255
 network 10.52.128.0 0.0.15.255
 redistribute static metric 10000 10 255 1 1500 route-map DEFAULT
!
no ip forward-protocol nd
ip route 0.0.0.0 0.0.0.0 10.11.2.250
ip route 10.11.5.0 255.255.255.0 10.11.22.237
ip route 10.11.18.0 255.255.255.0 10.11.2.250
ip route 10.11.60.0 255.255.255.0 10.11.2.250
ip route 10.11.101.0 255.255.255.0 10.11.2.250
ip route 10.11.102.0 255.255.255.0 10.11.2.250
ip route 10.11.103.0 255.255.255.0 10.11.2.250
ip route 10.11.104.0 255.255.255.0 10.11.2.250
ip route 10.11.105.0 255.255.255.0 10.11.2.250
ip route 10.11.106.0 255.255.255.0 10.11.2.250
ip route 10.11.107.0 255.255.255.0 10.11.2.250
ip route 10.11.108.0 255.255.255.0 10.11.2.250
ip route 10.11.109.0 255.255.255.0 10.11.2.250
ip route 10.11.110.0 255.255.255.0 10.11.2.250
ip route 10.11.111.0 255.255.255.0 10.11.2.250
ip route 10.11.112.0 255.255.255.0 10.11.2.250
ip route 10.11.113.0 255.255.255.0 10.11.2.250
ip route 10.11.114.0 255.255.255.0 10.11.2.250
ip route 10.11.115.0 255.255.255.0 10.11.2.250
ip route 10.11.116.0 255.255.255.0 10.11.2.250
ip route 10.11.117.0 255.255.255.0 10.11.2.250
ip route 10.11.118.0 255.255.255.0 10.11.2.250
ip route 10.11.119.0 255.255.255.0 10.11.2.250
ip route 10.11.120.0 255.255.255.0 10.11.2.250
ip route 10.11.250.0 255.255.254.0 10.11.2.15
ip route 10.11.252.0 255.255.254.0 10.11.210.97
ip route 10.12.60.0 255.255.255.0 10.11.2.250
ip route 10.20.1.0 255.255.255.0 10.11.2.250
ip route 10.21.0.0 255.255.0.0 10.11.2.250
ip route 10.30.0.0 255.255.0.0 10.11.2.250
ip route 10.40.0.0 255.255.0.0 10.11.2.250
ip route 10.50.0.0 255.255.0.0 10.11.2.250
ip route 10.52.128.0 255.255.240.0 10.11.2.250

ip prefix-list STATIC seq 10 permit 0.0.0.0/0
ip prefix-list STATIC seq 20 permit 10.11.0.0/16 le 32
ip prefix-list STATIC seq 25 permit 10.12.0.0/16
ip prefix-list STATIC seq 30 permit 10.20.1.0/24
ip prefix-list STATIC seq 40 permit 10.21.0.0/16
ip prefix-list STATIC seq 45 permit 10.30.0.0/16
ip prefix-list STATIC seq 50 permit 10.40.0.0/16
ip prefix-list STATIC seq 60 permit 10.50.0.0/16
ip prefix-list STATIC seq 70 permit 10.52.128.0/20

Any suggestions would be greatly appreciated!

Seb Rupik · ‎08-05-2021

Hi there,

You only have a single static route to the the 10.12.60.0/24 subnet, this will not match your existing prefix-list entry for 10.12.0.0/16. you need to update your prefix-list to match the mask range /16 - 24:

!
ip prefix-list STATIC seq 25 permit 10.12.0.0/16 le 24
!

cheers,

Seb.

BeckyBoo123 · ‎08-09-2021

@Seb Rupik Thank you for the suggestion. I changed the prefix list entry as suggested and then I was able to see my local network but I think there must be some restriction on my firewall still as I cannot see beyond the physical location I am at.

All of my firewall rules allow traffic to flow though the 10.11.0.0/16 subnet but maybe I need to add 10.12.0.0/16 also to these rules?

I don't want to mess too much in one go as its a live environment and also I don't want to go and put 10.12.0.0/16 in everywhere if its not needed.

Seb Rupik · ‎08-09-2021

With just the contents of the eigrp process it is hard to determine the topology of your network and know where the firewalls are sitting.

Do you have a diagram?

Certainly adding the 10.12.0.0/16 to any rule which mentions 10.11.0.0/16, but since 10.12.0.0/16 is for voice it is highly likely that your will grant it far more access that those devices would require.

cheers,

Seb.

Patterson56 · ‎08-05-2021

By decreasing the existing bits that are part of the default subnet mask it will allow you to. ... At present you must use dhcp to assign new ip addresses.

Target Gift Card Balance

BeckyBoo123 · ‎08-09-2021

@Patterson56 The final goal is to use DHCP but I cannot reach the server yet to obtain a lease.

Giuseppe Larosa · ‎08-09-2021

Hello @BeckyBoo123 ,

on the L3 interface for new subnet 10.60.12.0/24 you need

ip helper-address 10.11.202.1

this is needed to make unroutable DHCP requests arriving with destination address 255.255.255.255 (broadcast) to be converted in unicast packets with destination the DHCP server.

This feature is called DHCP relay agent and it is a great part of the success of centralized DHCP servers

Hope to help

Giuseppe