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New Member

3750 Routing issue

Home office:

3750 switch - /

default gateway for the network

(2) Vlans, 30 for IP phones and 110 for workstations.

Pix 515E firewall - /

Remote office:

Pix 506 firewall - /

There is a vpn setup between the two Pix firewalls. I can ping from the home office 3750/Pix to the remote Pix 506 and vica versa.

I can ping from a host on the network to the Pix 515/3750 switch, but not to any hosts on the network. I also cannot ping from any host on the network to the network.

If I add a static route to a host on the network pointing to either the Pix 515 or 3750 as the next hop for the network, that host can then ping the Pix 506.

It seems like I'm missing something right in front of me.

The switch config is attached.


Re: 3750 Routing issue

Hi ,

Ip helper-address is configured under vlan30.i.e

interface Vlan30

ip address

ip helper-address

no ip route-cache

no ip mroute-cache

Do you have DHCP server in network.



New Member

Re: 3750 Routing issue

Yes, is the dhcp server on that net. I'm not sure why there is a helper address in the config. I just inherited this environment, so I'm still getting familiar with it.

The more I look at this, I have a feeling it has something to do with both locations using the 10.x.x.x range, even though they have different masks.


Re: 3750 Routing issue

Hi ,

Accroding to the following document ip helper-address should be DHCP server ip.

Check the below link.

One common application that requires helper addresses is Dynamic Host Configuration Protocol (DHCP), which is defined in RFC 1531. DHCP protocol information is carried inside of BOOTP packets. To enable BOOTP broadcast forwarding for a set of clients, configure a helper address on the router interface closest to the client. The helper address should specify the address of the DHCP server.

Hope it helps you.



New Member

Re: 3750 Routing issue

I'm not having any issues with dhcp, but I did correct that entry to reflect the proper ip of the dhcp server.

This also did not have any affect on my issue.


Re: 3750 Routing issue

I don't see any layer 2 vlans defined . If you do a "show vlan" do both vlans 30 and 110 show active with ports assigned to them ?

Re: 3750 Routing issue


In which vlan does u r PIX connected on 3750.



New Member

Re: 3750 Routing issue


Your Homeoffice IP range includes your remote network 10.x.y.0/25.

Your have a routing issue. change the homeoffice mask to /16 or /24



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