Ok,
So I have no clue how to do this and it's been thrown at me. We had a router that used a T1 apparently and behind the router is a PIX515. I did a show run on the router to see the current config. Can I use the existing serial port controller for the new cable line or should I put it on FE0/1? We got these IP's from Comcast:
173.13.19.81
255.255.255.248
GW: 173.13.19.86
How do I config the router for this new connection? I know all I have to do on the PIX is change the old WAN IP's to the new ones. But the router.....
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Reading more carefully, the best option is to just take the router out of the picture. It was needed to provide connectivity between the PIX's ethernet and the T1's serial, but won't be with Comcast.
I would just assign the Comcast IP address and default gateway to the PIX's outside interface and plug that directly into the cable bridge, bypassing the router entirely.
I think you posted before my second comment showed up. The T1 gave you two networks, one for the T1 itself (216.234.103.148/30) and one for the Ethernet between the PIX and the router (216.234.116.120/29). Comcast is giving you only one network to work with, so if you want to keep using the router, we'll have to configure it to bridge the FastEthernet ports. This is really unnecessary and gives you nothing but an additional point of failure in your network. I would just put the Comcast IP on the outside interface of the PIX, change the default router on the PIX to the one provided by Comcast and plug the cable bridge directly into the outside interface of the PIX.
Ok, on the PIX I have the outside interface set to 173.13.19.86 because the block I got from Comcast is 173.13.19.86/29
Is there something I have to do on the modem itself? Looks like it is serving DHCP under a different scope (10.1.10.1/25). I'm assuming I need to disable DHCP for the LAN right? Then just go from one of the LAN ports to the outside interface on the PIX?
You shouldn't have to do anything on the cable device itself. The last time I worked with one of those, it would serve a private IP address range via DHCP but would operate as a bridge if the internal device was using public IPs. If you configure the PIX with the public IP and proper default router, you should be good. If not, let me know the make and model number of the cable device you're using and I'll see if there's anything special that needs to be done.
Nope. That looks correct. The Comcast box should bridge any requests from the LAN using the public IP addresses to the WAN... or at least that's the way the last Comcast box I worked on did it. If it's not working, let me know the make and model of the Comcast box and I'll see if there's anything special that needs to be done.
Okay... that's not the same model I worked with last time. I did some reading on what to do with the 8014 and ran across this helpful thread on dslreport.com.
http://www.dslreports.com/
If you can make the Comcast device pass traffic directly, which is normally done with bridge mode but seems to be a little bit different on the 8014, then the PIX will start communicating directly.
Have a closer look at the second comment in the thread. There's no using 10.1.10.0 addresses on the PIX, just the assigned static IP address.
A number of other posts I've been looking at have indicated that the tech support guys at Comcast will make the 8014 work in bridge-mode (or the closest thing that the 8014 approximates) for you so that you can pass the public addresses in... which saves you a lot of headaches.
It's not so much that something is *wrong* on the Comcast box as that it isn't set up correctly for your application. Did you ask Comcast to put the device in bridge mode so that you can use the public IPs on the LAN? If so and they were unable to assist further, try the following:
Plug a computer into one of the other LAN ports of the Comcast box and get into the web management interface on the unit. Go to the "SMC Firewall" setting and select "Disable Firewall for True Static IP Subnet Only" and see if that gets everything up and running.
Many others have made this configuration work, so it's just a matter of hammering out the details. Shouldn't take too long to figure out where the wrench in the gears is.
I got it working. Comcast is stupid. I just did NAT translations on the modem itself and gave the PIX a LAN IP from the modem and put it in the DMZ host so it can get out. All my clients go through our proxy anyway. But proxy, VPN and FTP are all working. Thanks for your help, i'll reward you the points.
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by: jodylemoinePosted on 2009-09-30 at 09:17:57ID: 25460435
You're going to have to use the FastEthernet0/1 connection for a cable line. T1 connections are serial (hence the use of the serial port) but a cable connection is going to give you an ethernet connection from the cable bridge.