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New Member

Cisco 2801 Routing between two Ethernet Interfaces

I have a Cisco 2801 router with two ethernet interfaces in it. I applied the IP addresses given to me from my ISP on fa0/1 interface and set my default route to point to their router. I then applied the other ip addresses given to me from the ISP that are my "usable" addresses for my firewall, web servers, etc. on fa0/0. I can ping anything from fa0/1 using source IP ping to the ISP and anything on the web from the router. I have installed rip and applied both network addresses into the rip router. I cannot ping from one ethernet interface to another. I can ping to fa0/0 from a workstation and that works fine. So it seems just to be between the two interfaces.

Here is a portion of my config (Not real addresses of course)

interface FastEthernet0/0

description Network Uplink

ip address 192.168.1.200 255.255.255.240

duplex auto

speed auto

!

interface FastEthernet0/1

description WAN Port

ip address 192.168.10.50 255.255.255.252

speed 100

full-duplex

!

ip route 0.0.0.0 0.0.0.0 192.168.10.49

What would be my static route between the two ethernet interfaces? I am a little confused to I point my static route from 192.168.1.200 to 192.168.10.50 ?

Thanks for the help,

Scott

8 REPLIES
Hall of Fame Super Silver

Re: Cisco 2801 Routing between two Ethernet Interfaces

Scott

Am I correct in understanding that your provider has given you 2 address blocks, one with a small mask (252) and one with a slightly larger mask (240)? And am I correct in understanding that both the FastEthernet interfaces show as up/up?

Are the end stations that are connected to interface FastEthernet0/0 configured with addresses in that subnet and with the 240 mask? Can you tell us what they are configured with for default gateway?

When the symptom is that end stations that are connected on FastEthernet0/0 can ping that interface and can not ping FastEthernet0/1 the first thing that I would look for is an incorrect default gateway on the end stations.

HTH

Rick

Hall of Fame Super Bronze

Re: Cisco 2801 Routing between two Ethernet Interfaces

Scott,

Per your description, you are routing between fa0/0 and fa0/1 since you are able to ping devices in the internet from the router. Fa0/1 is the gateway to the internet.

Do you have any access-group applied on that interface ?

If you issue a 'show ip route', Fa0/1 network listed in the routing table ?

Bronze

Re: Cisco 2801 Routing between two Ethernet Interfaces

Hi scot,

Your both ethernet interface are directly connected to each other, you dont need any routing to ping each other

I Think its ur Speed and Duplex setting on both interfaces are different, Try setting both to Auto and check to ping.

Hope this helps

Raj.

New Member

Re: Cisco 2801 Routing between two Ethernet Interfaces

So I don't need any static routes even if both ethernet interfaces are on different networks? I did thry the speed and duplex settings but still no luck.

Thanks

Scott

Hall of Fame Super Bronze

Re: Cisco 2801 Routing between two Ethernet Interfaces

No, you don't. Can we see the

show ip route

as well as

show ip interface brief

Hall of Fame Super Silver

Re: Cisco 2801 Routing between two Ethernet Interfaces

Scott

No you do not need any static routes to route between connected intefaces.

In my previous post I asked about how the end stations were configured. Can you confirm the configuration of the end stations for their IP address, netmask, and (most especially) their default gateway).

the most common cause of symptoms such as you describe is incorrectly configured default gateway on the end stations. Please confirm what is configured for default gateway on the end stations.

HTH

Rick

New Member

Re: Cisco 2801 Routing between two Ethernet Interfaces

Thanks for the help guys, I got it fixed. I had done two configs one with static routes and the other with just my default route to the next router.

It was a problem with the ISP, they did not have the second set of IP addresses setup on their end to point back to the gateway. Once they got their end corrected everything started working.

I thought this was a pretty simple config but sometimes you need a second look from some other people.

Thanks for the help,

Scott

Hall of Fame Super Silver

Re: Cisco 2801 Routing between two Ethernet Interfaces

Scott

Thanks for posting back and indicating the solution to your problem. It makes the forum more useful when we can read about a problem and can see what the solution was.

I believe that your issue is not uncommon - to have problems in a new address block that the provider does not have routing to you for it set up properly at first. I am glad that you got it worked out.

HTH

Rick

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