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New Member

ISA570W static route to Comcast gateway/modem

I believe this is a static route question.

I am looking to be able to login to the Comcast Gateway/Modem (10.1.10.1) from any connected computer on my network. Currently I am unable to do this, I am also unable to ping the Comcast device. Here is my setup.

Comcast Device (SMC8014)

WAN IP: 50.x.x.238

LAN IP: 10.1.10.1 (255.255.255.0)

One CAT5E cable to:

ISA570W (WAN Port) - (Basic out-of-the-box setup, 1-WAN, 1-DMZ, 8-LAN Ports)

STATIC WAN Port Info:

WAN IP: 50.x.x.233 (255.255.254.0) Gateway: 50.x.x.238

LAN IP: 10.1.10.2 (255.255.255.0)

DHCP Enabled for Default VLAN-1 (10.1.10.30-99) Gateway: 10.1.10.2

One CAT5E cable to:

Cisco SG200-50P (POE Switch to serve connections to phones and desktops)

LAN IP: 10.1.10.3 (255.255.255.0)

So the devices on my network get an IP from the ISA device, the ISA is also the default gateway. I have logged into the Comcast device and all firewall rules and blocking are disabled.

Here is a copy of my current routing table according to the ISA570:

Destination Address

Subnetwork AddressGatewayFlags*MetricInterface

192.168.3.0

255.255.255.0

0.0.0.0

U

0

DMZ

10.1.10.0

255.255.255.0

0.0.0.0

U

0

DEFAULT

10.1.1.0

255.255.255.0

0.0.0.0

U

0

VOICE

192.168.25.0

255.255.255.0

0.0.0.0

U

0

GUEST

50.x.x.0

255.255.254.0

0.0.0.0

U

0

WAN1

127.0.0.0

255.0.0.0

0.0.0.0

U

0

LOOPBACK

0.0.0.0

0.0.0.0

50.x.x.238

UG

0

WAN1

So from my desktop (10.1.10.32) I am unable to ping or login to the comcast device at 10.1.10.1.

So I believe I am missing something simple here, is this a static route solution, or am I looking at NAT policies?

Thanks for your help and please let me know if you need any more information about my network.

-Matthew-

Everyone's tags (4)
1 ACCEPTED SOLUTION

Accepted Solutions

ISA570W static route to Comcast gateway/modem

Ok, a few possibilities here.

  1. Did you go through this process to switch the SMC8014 to Bridge mode?
  2. I would recommend using a different subnet on the ISA LAN interface than the 10.1.10.x.  The reason for this is that when you send a request from a 10.1.10.x subnet behind the ISA to a 10.1.10.x subnet, both your PC and the ISA assume the device is on the same network and won't try to route it.  Consider using the default 192.168.75.x subnet on the LAN interface of the ISA.

If you didn't complete step 1 above, then I'm pretty certain you will be unable to browse the internet at all.  If you can browse the internet but just can't get to the 10.1.10.1 Comcast router, then odds are step 1 is already complete.

Shawn Eftink
CCNA/CCDA

Please rate all helpful posts and mark correct answers to assist others searching for solutions in the community.

Shawn Eftink CCNA/CCDA Please rate all helpful posts and mark correct answers to assist others searching for solutions in the community.
10 REPLIES
New Member

ISA570W static route to Comcast gateway/modem

Hello Matthew,

Can you tell me which ports you are connecting the ISA to the Comcast device with (LAN or WAN)? Hopefully I'll be able to answer more with this information.

Zach Baumgartner

New Member

ISA570W static route to Comcast gateway/modem

Zach,

Thanks for the quick response. One cable goes out of the Comcast device to the WAN port of the ISA.

Regards,

-Matthew-

ISA570W static route to Comcast gateway/modem

Ok, a few possibilities here.

  1. Did you go through this process to switch the SMC8014 to Bridge mode?
  2. I would recommend using a different subnet on the ISA LAN interface than the 10.1.10.x.  The reason for this is that when you send a request from a 10.1.10.x subnet behind the ISA to a 10.1.10.x subnet, both your PC and the ISA assume the device is on the same network and won't try to route it.  Consider using the default 192.168.75.x subnet on the LAN interface of the ISA.

If you didn't complete step 1 above, then I'm pretty certain you will be unable to browse the internet at all.  If you can browse the internet but just can't get to the 10.1.10.1 Comcast router, then odds are step 1 is already complete.

Shawn Eftink
CCNA/CCDA

Please rate all helpful posts and mark correct answers to assist others searching for solutions in the community.

Shawn Eftink CCNA/CCDA Please rate all helpful posts and mark correct answers to assist others searching for solutions in the community.
New Member

ISA570W static route to Comcast gateway/modem

Shawn,

Also thanks for the quick reply.

Yes I found those articles as well when doing  a little research on this problem. I have logged into the Comcast device and verified that it is setup in the bridged mode.

I agree with #2, I probably should have my ISA on a different IP/Subnet. Initially I thought that if i put them on the same then it would make it easier to configure the route (if needed at all) to be able to login to all devices on this network.

Thanks again!!

-Matthew-

ISA570W static route to Comcast gateway/modem

Try changing that LAN Subnet on the ISA and see if it works.  It's possible it may or may not work.  If it still doesn't work, try creating a Static Route for 10.1.10.0 / 255.255.255.0 with a Gateway of 50.x.x.238.  It shouldn't need that, but just in case it still doesn't work, you can try it.

Shawn Eftink
CCNA/CCDA

Please rate all helpful posts and mark correct answers to assist others searching for solutions in the community.

Shawn Eftink CCNA/CCDA Please rate all helpful posts and mark correct answers to assist others searching for solutions in the community.
New Member

ISA570W static route to Comcast gateway/modem

Matthew,

I tested this using an RV042G instead of the Comcast device and I was able to get it to work, so hopefully it will work for you. Plug the modem into a LAN port of the ISA. Do not use the WAN port of the ISA at all. The DHCP server of the modem should be turned off. The LAN IP address of the modem, ISA, and switch should all be static. The default gateway of the ISA's LAN should be the modem (10.1.10.1). The default gateway of the switch should be the ISA (10.1.10.2).

I was able to plug my computer into the switch and recieve an IP address from the ISA. I was able to access the internet, and ping the router (in your case, Comcast device). Let me know if that works.

Zach Baumgartner

New Member

ISA570W static route to Comcast gateway/modem

Zach and Shawn,

I will try both of those tonight when everyone has left the office. I will update you tomorrow with the results.

Thanks again for your help and prompt replies.

Regards,

-Matthew-

Re: ISA570W static route to Comcast gateway/modem

Zach,
Correct me if I'm wrong here, but by doing that, you're basically not using the firewall functionality of the ISA at all. You're just using the switch portion and DHCP of the ISA and still using the NAT and Firewall in the SMC device. It would be no different the just plugging the SMC into a switch and turning DHCP back on in the SMC. Am I missing something?

Sent from Cisco Technical Support iPhone App

Shawn Eftink CCNA/CCDA Please rate all helpful posts and mark correct answers to assist others searching for solutions in the community.
New Member

ISA570W static route to Comcast gateway/modem

Zach & Shawn,

Thanks for all your help on this. Last night I just changed the ISA570 IP to a different subnet (10.1.2.2). Everything is working fine now. I still believe that there is a way to make that route work, but oh well.

Regards,

-Matthew-

ISA570W static route to Comcast gateway/modem

Matthew,

I'm thrilled to hear that you now have everything working.  If there were any helpful posts, would you mind rating those and if we were able to provide a correct answer for you, would you mind marking the correct answer.  This helps other community users to more quickly remedy similar challenges.  Thank you for working through this with us.

Shawn Eftink
CCNA/CCDA

Please rate all helpful posts and mark correct answers to assist others searching for solutions in the community.

Shawn Eftink CCNA/CCDA Please rate all helpful posts and mark correct answers to assist others searching for solutions in the community.
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