Cisco Support Community
Community Member

can't route through an 877 with no NAT

hi there,

I'm trying to setup an 877 to sit in front of a firewall. As the firewall has a public IP I do not want to use NAT.

The problem I'm having is I can't seem to route through the 877.

From the 877 i can ping

From the internal network I can ping the dialer0 interface of the 877 but cannot ping

I will attach the config - can anyone help with this?




can't route through an 877 with no NAT

Reading your issue and reading you config - I would like to ask a question.....

Your LAN on the 877 facing the firewall has an IP of ip address X.X.17.170 so your firewall Outside IP address is  ip address X.X.17.169

That's OK - but on your router.....


interface Dialer0

ip address negotiated

So you are getting a DHCP address, your firewall will have a default gateway of the router, the router has a default gateway of the ISP and the dialer0 IP address. So how does your ISP know how to route X.X.17.169 to your Dialer0 interface???

Community Member

can't route through an 877 with no NAT

Hi , huwyhuwy123

I'm not sure you have help,

Did you mean,

Do you want your firewall settings? .

What is destined to set a route on the firewall XX17.170 ?

What is the policy of the firewall settings permit PING(ICMP) ?

CreatePlease to create content