C

Visitor

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14 Messages

Monday, November 8th, 2021 4:15 PM

Closed

VPN Not Working

I have the same problem like many others with VPN over Xfinity. None of my three laptops can VPN from home to work. But they work if I switch to using signal from my T-Mobile phone with USB tethering.

Laptop #1 was working with VPN for several years and stopped working about 4 months ago. When it worked, it only worked with ethernet cable connecting directly to Xfinity cable modem. Did not work with Wifi signal. During the time that laptop#1 was working flawlessly with Xfinity, I could not get any other laptop to work with VPN. Even more strange, for a short period of time, it did not work if I connected using the pop up screen from the Windows taskbar network icon. I had to connect using the VPN screen under the Windows Settings App.

Laptop #2 was bought recently and able to VPN "ONCE and just ONCE" about 2 months ago (during the time that laptop#1 did not work) but then stopped working. The only way to get VPN to work is to use my T-Mobile phone network through USB tethering/hotspot.

Laptop #3 has never worked with Xfinity. Only works with phone signal through USB tethering/hotspot.

Deactivating xFi Advanced Security does not help.

Several employees at our company have same issue. They can't connect to work through VPN from home.

Furthermore, I am the sever admin. I know for sure it is not the server issue. 

I have fought this issue for several years with countless internet researches to no prevail. The problem is so random, that it is hard to pin down to Xfinity. But I wish Xfinity subject matter experts can look into this and helps us out. All tips that I could find from this forum have lead to the dead end.

This post was created from this comment on different post

Problem Solver

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948 Messages

3 years ago

So, i use several different VPNS on Comcast, most of them work without a issue, here is a couple of of variables to think about, a VPN can use a couple of different  protocols to connect to the VPN,  example, tcp or udp etc, different protocols can be slower or a lot faster, you can usually set them in the settings of your VPN, the thing  is every different protocol might not work, you have to experiment to see what really works for your VPN, i have found some of the faster ones might quit working because different VPN server locations might or might support them. Then there is server locations, on my VPNs i can pick a location anywhere in the world, so occasionally one might quit working, it might show connected but its really not, i just change to a different location and i am up and running with a few clicks, some VPNs have what is called a 'kill switch', so if it looses connection it blocks all internet traffic, that way you don't unknowingly send maybe sensitive information over the internet if your VPN fails. You have to examine what is set by default on your particular VPN and maybe adjust some setting. I have had them working for months/years then quit working, i just check what i posted above and usually its fixed with a few clicks, just a thought   

(edited)

Problem Solver

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571 Messages

@jlavaseur So sorry to hear of the troubles you are having! Your VPN provider may require specific security or firewall settings in order to connect successfully. Contact your VPN provider and work with their IT for further configuration details. Here is a great link with more information regarding connecting to a VPN: https://comca.st/2YGFBbO

I no longer work for Comcast.

Problem Solver

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948 Messages

@XfinityAlisha I don’t have any problems, I was stating possible fixes or things to investigate from personal experience 

Official Employee

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3.5K Messages

Our apologies and thanks for letting us know! 

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
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Expert

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104.5K Messages

@XfinityAlisha

The original poster @ChauBaby is the one with the problem. 

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
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Visitor

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10 Messages

3 years ago

It sounds like this is a company hosted VPN. If so, you will also want to involve your IT Dept. in the troubleshooting. Depending on the way the VPN is set up, you could have several blockers on the company side. Such as only having one device connected at a time or only being able to connect with a trusted device. There are even variables of how many people can be connected to the VPN at one time for certain providers / equipment as well. 

With that said, it would be very hard to troubleshoot without seeing the event logs from the VPN company side on the connections.  

Visitor

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14 Messages

@hsmith199 Thanks for your response. I am actually am the company VPN admin. It does not work even when there is no other computer connected to the server. Like I described above, it works through mobile phone network. So that rules out the issue on the server side.

Official Employee

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1.6K Messages

Hi, @ChauBaby. We know we have many customers that work from home, and we don't have anything set up to proactively prevent any specific VPN from working on our network. In addition, we have employees that work from home too that need to use a VPN on the Xfinity network daily. Is this only with the VPN provided by your employer, or have you had trouble with a personal VPN you pay for on your own as well? 

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

Visitor

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14 Messages

@XfinityVianney This VPN is provided by the company. It is using Godaddy VPN. I don't have a personal VPN.

Problem Solver

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574 Messages

Thanks for clarifying. We don't have any blocks in place for Godaddy on our end. You may need to try further troubleshooting with the VPN or contact Godaddy since the internet connection to the home otherwise is solid.  

I no longer work for Comcast.

Visitor

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14 Messages

@XfinityBiancaB I am able to establish VPN connection using my mobile phone network instead of Xfinity. This eliminates Godaddy being an issue.

Visitor

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14 Messages

3 years ago

Tried with new gateway address 192.168.0.1 today but no still no luck. May have to revert back to 10.0.0.1.

It was suggested that the VPN provider GoDaddy may be blocking Comcast assigned WAN / public IP address for whatever the reason may be. I will contact Goddady and see.

Visitor

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14 Messages

3 years ago

Spending the last couple days to crack the VPN issue with no success, I finally ran to Xfinity store today and swapped my XB7 modem with another XB7 as suggested by Xfinity Support as well as having my internet plan upgraded from 400/10 to 600/20. Just to try my luck.

All computers are now able to establish VPN connection to the remote server. But only one computer at a time. Apparently only a single tunnel can be established between the two ends. All computers work fine with ethernet or WiFi connection.

The problem was definitely on the home Xfinity. May be a bad modem. Or may be just a hard reboot. Or may be some configuration changed with a new upgrade. I will plug back the old modem in to test it out at some point just for curiosity.

Wireshark is an extremely useful tool. In my case, it helps to confirm my home computers are talking to the VPN server through real time packet transmission between the two ends and not just dead somewhere.

Thanks for all the help from the Xfinity Support team.

(edited)

Expert

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104.5K Messages

@ChauBaby

FWIW, when you connect up a new / different router / gateway device it has a different MAC address which forces the Comcast DHCP server to assign a new / different WAN public IP address to your connection. Perhaps GoDaddy was indeed blocking your previous WAN / public IP address for whatever the reason may have been.

You wrote: "All computers are now able to establish VPN connection to the remote server. But only one computer at a time. Apparently only a single tunnel can be established between the two ends."

FWIW. This is a common security limitation of many VPN services. 

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick

Visitor

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14 Messages

@EG I actually contacted Godaddy and they insisted that it has nothing to do with them. To eliminate Goddady being a problem, I bypassed Godaddy and VPN directly to our server using server WAN IP address. This is just a simple L2PT client to server VPN connection. Our server is Ubiquiti Network with UniFi Security Gateway and I should be able to connect directly from Windows VPN. It did not work with the old modem but works with the new one. This test pretty much eliminates Godaddy.

Expert

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104.5K Messages

@ChauBaby

@EG I actually contacted Godaddy and they insisted that it has nothing to do with them.  

Well we've heard that one many times here before too. It's always pretty much a hot potato game. 

Just stating the facts about the way their DHCP / IP address assignment works.

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

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Visitor

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14 Messages

@EG, Just want to circle back and close out your speculation. It was the VPN issue that you suspected that Godaddy might have blocked the IP address. 

I am now confident that this has nothing to do with Godaddy.

We recently had a new IP address at work and this time I VPN directly from home to work using default windows VPN application. No Godaddy whatsoever. It is 100% Comcast connection. Both home & work have Comcast service. VPN had worked perfectly since the replacement of the home Comcast modem until last Friday. Luckily, I still have the old modem. I put back the old modem, ran set-up, blah-blah, and bingo. VPN is back working again. I still don't know what caused the problem. As Comcast would not do anything to block VPN. But this at least eliminates Godaddy.

Visitor

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14 Messages

2 years ago

Something blocks my VPN from home to work. I highly suspect the issue is within Comcast.

This is the third time I have to swap the xFinity modem at home in order to get VPN to work. Literally just to get the modem to redo the set up. After each set up, the modem got a new WAN IP address. The WAN Default Gateway address was sometime the same, sometime different.

I can eliminate the computer being the issue because I have two computers at home. Either both work or don't after each modem reset.

I can eliminate the work server being the issue because I am the server admin. I do not block any address. 

When VPN is not working through Comcast network, I can manage to get VPN connected through my mobile network.

Hate to point a finger to Comcast without a direct evidence, but by elimination, it points to Comcast.

My temporary fix right now is keeping two xFinity modems and manually swapping them when VPN is not working.

I hope VPN user having similar issue can try this fix and share back the result.

Many people having VPN issue. Not just me.

https://forums.xfinity.com/conversations/your-home-network/urgent-vpn-not-working/602daf72c5375f08cd0c69d7?page=1

I hope Comcast can look into this. They have insisted that they don't block anything but they seems to know there is an issue.

https://forums.xfinity.com/conversations/your-home-network/vpn-blocked/602db078c5375f08cd2f1666

Note: This comment was created from a merged conversation originally titled VPN Blocked

(edited)

New Poster

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2 Messages

2 years ago

Let me ask, is the home user using comcast as thier isp and is also the destination network using comcast isp?  I am running into an issue where vpn works fine except for specific ips in the 10.1.10.x subnet.  The home users have a 10.0.0.x ip.   Im thinking that the destination router has a 10.1.10.x subnet even though it is in bridge mode and might be causing the issues.  Im going to dig into it today.

Expert

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104.5K Messages

@crocknroll​ 

Please create a new topic of your own here on this board detailing your issue if you wish. Thanks. The original poster has not returned. 3-month-old dead thread is now being closed.
  

(edited)

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
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