topic Re: how to configure a firewall for a local network with multiple subn in Network Security

how to configure a firewall for a local network with multiple subnets?

araujo180 — Fri, 10 Jan 2025 15:01:08 GMT

hi need some help with configuration of this firewall i already use the basic configuration and it doesn't let anything pass through . the network in the top is the outside and the one on the bottom should be the outside. I don't know if I have to change anything in the configuration of the firewall or maybe in the topology of the network. if you know how to do this please let me know.

Re: how to configure a firewall for a local network with multiple subn

Flavio Miranda — Fri, 10 Jan 2025 15:09:50 GMT

@araujo180

Hard to say anything without seeing the configuration. But, at least you need access-list and access-group applied to the outside interface.

You can attach yout PAcketTracert file here and I can take a look. Just zip it first.

Re: how to configure a firewall for a local network with multiple subn

araujo180 — Fri, 10 Jan 2025 15:34:24 GMT

@Flavio Miranda

here is the file i would really appreciate if you could help me to know what i need to do. also i need to configure the firewall as a dhcp server if you can help me with that to i would really appreciate it.

Re: how to configure a firewall for a local network with multiple subn

Flavio Miranda — Fri, 10 Jan 2025 15:34:37 GMT

I will. Just need a few hours as I am out of my computer now. Will let you know

Any special reason to use the firewall as DHCP server?

Re: how to configure a firewall for a local network with multiple subn

araujo180 — Fri, 10 Jan 2025 17:24:49 GMT

its basically for an online lab that i am doing that ask for it and i dont know if have to change the normal configuration in this case.

Re: how to configure a firewall for a local network with multiple subn

Flavio Miranda — Fri, 10 Jan 2025 17:52:03 GMT

@araujo180

Your firewall seems to be fine. What I found missing was route on routers. I dont see the need for DHCP on firewall but if you reallly need to put DHCP server on firewall just tell me which network will be attended with Firewall as DHCP.

For now, you setup seems pretty decent to me.

Re: how to configure a firewall for a local network with multiple subn

araujo180 — Fri, 10 Jan 2025 18:36:58 GMT

well the networks that need the firewall to provide dhcp are the three in the bottom. so for the routers I need to add route to outside the network?

Re: how to configure a firewall for a local network with multiple subn

Flavio Miranda — Fri, 10 Jan 2025 18:55:25 GMT

@araujo180

I tried to setup the ASA as DHCP but it seems it only offer DHCP for the direct connected network, as we can see on the message below

"Address range subnet 192.168.1.10 or 192.168.1.100 is not the same as inside interface subnet 200.168.0.1"

Meaning, you can not provide DHCP for remote network which is the case for you scenario.

About the routes, I added two static route. One in the router4, connected to outide

ip route 0.0.0.0 0.0.0.0 200.168.0.1

and another one on the router5

ip route 0.0.0.0 0.0.0.0 201.168.1.1

And I redistributed both route on the RIP.

router rip

redistribute static

Re: how to configure a firewall for a local network with multiple subn

araujo180 — Fri, 10 Jan 2025 19:11:28 GMT

ok now what was happening thanks you very much for your help.