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Can ping outside network from switch but not from pc connected to It.

I've connected a dslmodem/router to a fast ethernet port(fa0/1) on a 2620 router.There is a 2950 switch connected to the other port (fa0/0).I can ping the Internet via the router but and the switch but not from a host connected to the switch.I can't reach the dslmodem from the host pc.I've configured nat(overload) on the router but I'm sure I've done something wrong.

I've attached the running config.Thanks

1 ACCEPTED SOLUTION

Accepted Solutions

Can ping outside network from switch but not from pc connected t

Config wise I can only suggest two changes:

- Change the ACL "access-list 7 permit 192.168.9.0 0.0.0.50" to

access-list 7 permit 192.168.9.0 0.0.0.255

- Change the following statement "ip nat inside source list 7 pool ovrld overload" to

ip nat inside source list 7 interface fa0/1 overload

Hope it helps

Neeraj

8 REPLIES
Hall of Fame Super Gold

Trying to connect Cisco Router to dslmodem/router

Duplicate post. 

New Member

Re: Trying to connect Cisco Router to dslmodem/router

Ok , I've edited the question! Still need some help with this one.

Can ping outside network from switch but not from pc connected t

Config wise I can only suggest two changes:

- Change the ACL "access-list 7 permit 192.168.9.0 0.0.0.50" to

access-list 7 permit 192.168.9.0 0.0.0.255

- Change the following statement "ip nat inside source list 7 pool ovrld overload" to

ip nat inside source list 7 interface fa0/1 overload

Hope it helps

Neeraj

New Member

Re: Can ping outside network from switch but not from pc connect

Hi.I changed the acces-list from 0.50 to 0.255 and It works!

Why wouldn't It work with the 0.50 ? It was working for the switch with the original .50 setting.The switch ends In .2 and the pc In .7.Both were within the parameters.What am I missing ?????

I haven't covered access lists yet.I assumed 192.168.9.0   0.0.0.50  means all the addresses between 0 to 50.From what I'm reading now thats totally wrong.It's to do with inverse subnet masks.Thanks for the help.

Can ping outside network from switch but not from pc connected t

well yes...on routers, ACL use WildCard Mask not the subnet mask and no this statement of yours is not correct "I assumed 192.168.9.0   0.0.0.50  means all the addresses between 0 to 50" its not that easy 

Wildcard mask is the opposite of Subnet mask i.e in binary format simply replace all 0's with 1 and vice versa. An easier way that I use to calculate wildcard mask is Subtrack each value in every octet from 255 and you will have the correct wildcard mask. Eg: 255.255.255.0 = 0.0.0.255 in wildcard, similarly 255.255.240.0 = 0.0.15.255 in wildcard mask

Do go through the ACL section as this is the basic rule that needs to be followed in any ACL on routers and Switches.

Best of luck

Neeraj

New Member

Can ping outside network from switch but not from pc connected t

I'll hit the books lol.Thanks for your help!

Bronze

Can ping outside network from switch but not from pc connected t

What is the setting on the PC? Does it get IP from DHCP or static? Check default gateway on PC.

Eugen

New Member

Can ping outside network from switch but not from pc connected t

Hi.No It's not that.It's static and the gateway Is correct.

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