Trying to understand Cisco Routing/Switching

fieryhail · 03-20-2009, 10:44 PM

Hello all, Excuse me for any ignorance that comes through, I'm extremely new to this and trying to absorb a lot, quickly. To summarize, I have broadband cable service, Static IP. I have 5 public IP addresses. The cable company (Optimum Online) provides a Cisco 851 preconfigured "married" to the cable modem. The c851 has a WAN port (which connects via ethernet to cable modem) and 4 FastEternet interfaces, this is to manage 5 static IPs. Go figure. Anyway, I currently have a D-Link DIR-655 Wireless/Wired router. I wish to continue using this as a WAP. I also have a Cisco 3662 router with 2 FastEthernet Interfaces (I'm looking at adding more interfaces, in futer via Network Modules). I also have a Cisco Catalyst 3550-48-G Layer 3 Switch. I also have a Linksys SD2008 8 port Gigabit switch that I'd like to use uplinked to the CAT3550-GBIC for a SAN box using iSCSI with multiple gigabit interfaces. Now that the hardware is done, what I want to do is to somehow (I don't know how, maybe with VLANs?) hook the c3662 to one of the ethernet interfaces on the c851, and have the c3662 be programmed to handle all 5 of my public IP addresses assigned me by my ISP. Then from the c3662 have the CAT3550 supplying the physical interfaces for all 5 public IPs as well as my private IP range for my internal LAN. One of my public IPs (the one that the DIR-655 currently handles 96.x.x.174) is the public IP that all the LAN clients access their internet from, both hardwired and wireless. My mail/groupware server is on a linux box on public IP 96.x.x.170. My web server is on another linux box using public IP 96.x.x.171. Can I assign certain ports on the CAT3550 to be as if I was plugging directly into one of the c851 ports? Somehow "porting" the IPs from the c851 into the c3662, then having the c3662 pump the IPs into the CAT3550 and have different Public IPs on different VLANs with additional ports on the CAT3550 associated with 1 VLAN (such as the DIR-655 with 1 WAN port and 4 LAN ports, can't I make a block of ports on te CAT3550 do the same thing and then have another "block" of ports on the CAT3550 as if another residential router was hooked up to another interface on the c851, this router supplying DHCP to it's clients while the previous DIR-655 is static with it's private LAN IPs. I know I'm being very confusing. Any help is greatly apprecited. Feel free to e-mail me at fieryhail@live.com. You can also reach me via AIM with the screen name fieryhail. Thanks again for any help!

03-20-2009, 10:44 PM	#1 (permalink)
fieryhail Registered User Join Date: Mar 2009 Location: New York Posts: 4 OS: OS X Leopard, XP Pro SP2(VM), CentOS 5.2 (VM), OpenSolaris 11.1 (VM)	Trying to understand Cisco Routing/Switching Hello all, Excuse me for any ignorance that comes through, I'm extremely new to this and trying to absorb a lot, quickly. To summarize, I have broadband cable service, Static IP. I have 5 public IP addresses. The cable company (Optimum Online) provides a Cisco 851 preconfigured "married" to the cable modem. The c851 has a WAN port (which connects via ethernet to cable modem) and 4 FastEternet interfaces, this is to manage 5 static IPs. Go figure. Anyway, I currently have a D-Link DIR-655 Wireless/Wired router. I wish to continue using this as a WAP. I also have a Cisco 3662 router with 2 FastEthernet Interfaces (I'm looking at adding more interfaces, in futer via Network Modules). I also have a Cisco Catalyst 3550-48-G Layer 3 Switch. I also have a Linksys SD2008 8 port Gigabit switch that I'd like to use uplinked to the CAT3550-GBIC for a SAN box using iSCSI with multiple gigabit interfaces. Now that the hardware is done, what I want to do is to somehow (I don't know how, maybe with VLANs?) hook the c3662 to one of the ethernet interfaces on the c851, and have the c3662 be programmed to handle all 5 of my public IP addresses assigned me by my ISP. Then from the c3662 have the CAT3550 supplying the physical interfaces for all 5 public IPs as well as my private IP range for my internal LAN. One of my public IPs (the one that the DIR-655 currently handles 96.x.x.174) is the public IP that all the LAN clients access their internet from, both hardwired and wireless. My mail/groupware server is on a linux box on public IP 96.x.x.170. My web server is on another linux box using public IP 96.x.x.171. Can I assign certain ports on the CAT3550 to be as if I was plugging directly into one of the c851 ports? Somehow "porting" the IPs from the c851 into the c3662, then having the c3662 pump the IPs into the CAT3550 and have different Public IPs on different VLANs with additional ports on the CAT3550 associated with 1 VLAN (such as the DIR-655 with 1 WAN port and 4 LAN ports, can't I make a block of ports on te CAT3550 do the same thing and then have another "block" of ports on the CAT3550 as if another residential router was hooked up to another interface on the c851, this router supplying DHCP to it's clients while the previous DIR-655 is static with it's private LAN IPs. I know I'm being very confusing. Any help is greatly apprecited. Feel free to e-mail me at fieryhail@live.com. You can also reach me via AIM with the screen name fieryhail. Thanks again for any help!