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m3_del's profile

Contributor

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20 Messages

Thu, Sep 17, 2020 5:00 PM

Bridge Mode inbound/ingress traffic issues

Hi, I recently received a speed upgrade to my service which came with a new Comcast supplied gateway. Previously I had been running on a modem I supplied. I was happy to see I could enable bridge mode for my service (I do NOT have static IP service). I set the gateway to bridge mode, plugged my laptop in directly first and viola! I had a public IP and blazing fast speeds. The tech left and I unplugged the laptop and plugged in my ASUS wifi router (3rd party). It too got a public IP form Comcast and all my outbound traffic worked great! Still blazing fast. We run a couple of simple web sites locally and have port forward rules setup on the ASUS router for forward port 80 and 443 to the appropriate server. This has worked great for the last 10 years and I had anticipated no problems with bridge mode enabled. Sadly that is not the case. While I can ping the IP my router receives, no web traffic is being passed through. I thought it could be something funky with the router connecting to the bridge mode. So I called tech support and unplugged my router from the gateway, and plugged my laptop (firewall disabled!!!!) into the gateway device. I spun up a simple hello world web service on port 80. Alas, still no traffic forwarded to my public ip that my laptop received! We disabled bridge mode, got a NAT'ed IP, setup a standard 80:80 port forward on the Comcast gateway device and of course that worked.

 

Long story short I want bridge mode to work so that all traffic is sent on to my ASUS router and to allow that to handle all the traffic/forwarding/etc. Double NAT and 1-to-1 NAT sound horrible and make my DDNS solutions less than elegant. HELP!

Responses

Accepted Solution

Contributor

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20 Messages

5 months ago

Welp, this is now resolved. I was in a meeting and notice my connection blipped. Logged into the gateway, checked out the logs. Saw that them mso user logged in and changed my mode back to bridged advanced and then bridged basic. Had my client try to access my web pages and it now worked. I even grabbed a tcp dump filtered on port 787 to show the now bridge mode success!Bridge Mode success!Bridge Mode success!

If all the techs did was switch back to bridge mode then I am at a loss as to what was happening. To future people with this issue. This is certainly a prove innocence model! I recommend creating tcp captures to illustrate the issue. Hopefully Comcast_ will be able to shed some light on what was occurring here! Thanks Comcast, I know I was a pain through this 😉 just needed resolution!

Official Employee

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136 Messages

5 months ago

Hi there! I'm so sorry for the delay. During this time we have a need for an increased support, but we are doing our very best to make sure we respond to you as soon as possible. Thanks so much for reaching out about your internet connection. You've absolutely reached the right place, and are in good hands. I will own this Issue for you and ensure that I provide the best help I can today. All I need is your full name, account number (follow link https://comca.st/3hI4SWc, account number is at the top right)and address including city, state, and zip code exactly how it reflects on the bill, and I can help you with whatever questions or concerns you may have. 

Contributor

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20 Messages

5 months ago

I can not see how to get you this info privately... so here it is. I will spell out my street numbers to try and obfuscate it.

 

I see I can PM you now... PM sent!

Contributor

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20 Messages

5 months ago

Just a note to say that I replied back to your DM to go ahead and reset/reboot the modem. Actually doo what you need to do when you need to as I really need this problem resolved. Thanks!

Contributor

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20 Messages

5 months ago

Hi, not sure if you all work weekends but hopeful for some help today. Adding in here what I have tried from a user standpoint so far. Also sent in my DM.

 

Here is the list of items I have tried either on my own or with a support associate on the phone with me.

 

Resetting the modem to factory settings

30-30-30 reset (older router trick)

In NAT mode (non-bridged), disabled the firewall, wireless and then enabled port forwarding (no entries, just enabled) then turned on bridged mode (both advanced and basic)

Straight up bridge mode both advanced and basic modes.

 

When I use NAT with my laptop hosting a port 80 web service I can set up port forwarding and external traffic flows [ Internet-> gateway IP -> internal IP on my laptop ]

When I enable bridge mode, my laptop gets a public IP as expected but traffic does not flow as expected [ Internet -> Laptop Public IP ]

 

One thing that stands out to me is that my router seems to have maintained the IP it had before I upgraded the speed of my service. Not sure if that is cause any problems or if there is a way to invalidate the DHCP lock to allow my router to snag a new IP. Complete speculation at this point. 

New Contributor

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13 Messages

5 months ago

I'm see the same issue at two client sites both sites have public IP's but I can't access any port forwards when I look at the logs I see the access I'm trying to make but from another IP on comcast's network. Do you have 4G backup from Comcast? I think its related to that because the two sites I'm seeing this at have that.

Contributor

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20 Messages

5 months ago

No 4G here. Not sure if the gateways is 4G capable though... here are my details.

 

The gateway model is: CGA4131COM

HW revision: 2.3

eMTA & DOCSIS Software Version:CM DOCSIS Application - Prod_18.3_d31 & MTA Application - Prod_18.3

Software Image Name:CGA4131COM_4.2p7s2_PROD_sey

New Contributor

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13 Messages

5 months ago

same hardware here.

 

Model:CGA4131COM
Hardware Revision:2.3

Visitor

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5 Messages

5 months ago

@m3_del I sent you a DM, but I wanted to post here for others to see as well.  I was able to resolve a similar issue (could not connect to VPN) by changing the modem from Advanced Bridge Mode to Basic Bridge Mode.  Thanks and good luck.

Contributor

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20 Messages

5 months ago

Thanks for the message! I switched back to basic mode this morning just to see if it made a difference. So far no luck.

 

Does anyone know the difference between basic and advanced mode? I can't find any information.

New Contributor

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13 Messages

5 months ago

Created a level 2 ticket, level 1 tech wanted me to turn of bridge mode to troubleshoot. Disconnected everyone from the internet and losing direct access to the internet for my VPN feature was not a step forward.

Official Employee

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234 Messages

5 months ago

Thank you for your patience and for that great question, Craig. After further research, I have discovered that the difference with the Advance Bridge mode is it leaves the Xfinity WiFi hotspot active.

Contributor

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20 Messages

5 months ago

Hi, are you referencing me? I have already messaged all my info. I was told Saturday I should hear from someone yesterday or today. I am hoping today! I believe I passed along my email and phone number...

 

Does anyone know the difference between basic and advanced bridge mode?

Official Employee

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348 Messages

5 months ago

Hi there :)! Thanks for taking the time to reach out to the Digital Care team here through the forums and we are so sorry to see that you are having some issues with your internet service. We do understand how important having reliable internet is and you have reached an amazing team to help! Can you please send us a private message with your name, the full address, and the phone or account number?