Sorry in advance for being verbose... Hopefully it helps you answer the question, though.
I was given a Cisco 1720 with no WICs. It has a built in ethernet port, console port, and aux port (some type of serial interface?).
My buddy couldn't remember the password to it, so I had to figure out how to access it via console cable and reset the password.
Anyway, I bought a 4 port switch (WIC-4ESW) for this thing to go in one of the WIC slots.
Then I discovered that the IOS had to be upgraded. So I had to get another friend to download the new IOS (lovely... Cisco won't let you just download it, you have to have special access). Anyway, I managed to get the IOS upgraded.
I figure I'm doing pretty well, considering I have never done any of this stuff before. My buddy with the Cisco account says he only knows PIX stuff, not IOS stuff. So I'm basically learning this on my own (with the help of the internet, of course).
At this point, I'm just trying to get a config that is similar to a cheap router that I've already got: A single WAN port gets a public address via DHCP and uses NAT/PAT to a four port switch.
I'm not sure if it's mandatory, but I want to use the vlan functionality of the WIC. My ultimate goal will be to split the switch into different vlans, so I want/need to learn it this way. So basically, my idea is to: configure interface for WAN configure DHCP server configure vlan configure interface for switch ports (add to vlan) configure interface for vlan (give IP, nat inside)
I'm having some trouble, I believe, with the WAN interface configuration. When I don't configure the interface at all, it somehow grabs an IP via DHCP. But I don't think it grabs the gateway address (default route?). I doubt it is getting the DNS servers either, but I don't know how to tell for certain. It's not as big of a deal as not getting the gateway since I can enter the DNS manually.
I can plug in to the switch and a client PC is given an IP address--it looks like the vlan and the dhcp are working.
I also think the PAT/NAT is working. I was able to ping across the "wan" interface when I did not try to configure it at all (factory defaults, except for I told it to nat outside). I plugged the WAN interface into my current network, and my 3Com router passed an address to the 1720. I could ping the 3Com and even access it's web interface. I couldn't surf the web or even ping any outside ip address, though, and I believe it is because the 1720 wasn't getting a gateway.
Please answer this for me: how do I, when configuring from a terminal, see what IP the router has gotten from it's DHCP server? I'd also like to see the dns and gateway IPs. Basically, is there a Windows "ipconfig" equivalent for the 1720?
So here's the config I've come up with: ! version 12.3 service timestamps debug datetime msec service timestamps log datetime msec no service password-encryption ! hostname gateway ! boot-start-marker boot-end-marker ! ! no aaa new-model ! resource policy ! memory-size iomem 25 ip subnet-zero ! ! no ip dhcp use vrf connected no ip dhcp conflict logging ip dhcp excluded-address 192.168.11.1 ! ip dhcp pool mydhcp network 192.168.11.0 255.255.255.0 default-router 192.168.11.1 domain-name mydhcp dns-server 68.87.64.196 68.87.66.196 ! ! ip cef ip domain lookup source-interface FastEthernet0 ! username WORD ! ! ! interface FastEthernet0 shutdown ip dhcp client client-id ascii WANDHCP no ip dhcp client request tftp-server-address no ip dhcp client request netbios-nameserver no ip dhcp client request vendor-specific no ip dhcp client request static-route ip address dhcp ip nat outside speed auto no shutdown ! interface FastEthernet1 switchport access vlan 11 ! interface FastEthernet2 switchport access vlan 11 ! interface FastEthernet3 switchport access vlan 11 ! interface FastEthernet4 switchport access vlan 11 ! interface Vlan1 no ip address ip broadcast-address 0.0.0.0 ! interface Vlan11 ip address 192.168.11.1 255.255.255.0 ip broadcast-address 192.168.11.0 ip nat inside ip virtual-reassembly ! ip classless ip route 0.0.0.0 0.0.0.0 FastEthernet0 no ip http server ! ip nat inside source list 1 interface FastEthernet0 overload ! access-list 1 permit 192.168.11.0 0.0.0.255 ! control-plane ! ! line con 0 line aux 0 line vty 0 4 login ! end