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shjin
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5 Messages

Tue, Aug 18, 2020 10:00 AM

Intermittent packet loss.

Kids started complaining a lot about dropping out of gaming sessions lately. And I also noticed Chrome browser sometimes shows No Intenet error intermittently. And my Microsoft Teams conference call often complains about bad network.  btw Both Nintendo Switch and my PC are using wired ethernet connection (1Gbps). So no wireless issue.

 

I followed https://forums.xfinity.com/t5/Your-Home-Network/Internet-Troubleshooting-Tips/td-p/3310447

But didn't succeed in solving this issue yet.

 

I am using XB6 and have 1Gbps service. The cable modem power level and SNR looked ok, but I tried removing the booster that was in as well as a filter designed to solve problem with multi-room DVR (because I don't have TV service anymore) and it didn't make any differences. With or without the signal booster, I see the same issue.

 

So I started monitoring ping responses for the following:

 

And when I observed the gaming session disconnet (probably packet loss), the ping showing "Request timeout" or "Destination host unreachable" from WAN router, www.google.com (IPv4) and www.engadget.com (IPv4) but not from google IPv6 ping.

 

And if I run speedtest from Speedtest.com, I get ping failure from those IP addresses more often. 

 

I am puzzled as to why IPv6 ping shows better reliability.

 

Now I am more convinced that this might be Xfinity (Comcast) side issue than devices in my household. Does this sound right to you? How should I go about fixing this issue further?

 

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shjin

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5 Messages

9 m ago

After countless fiddling with various things, it seems I finally solved this.

 

I felt that this isn't issue from any of devices inside my home and I suspected something wrong with WAN gateway that Comcast owns. 

 

I changed my router (Unifi Security Gateway)'s WAN MAC address to something else to force Comcast's DHCP give me new IP address that is associated with new WAN gateway. Note that I am using Bridge mode of XB6 modem.

 

This gave me new IP and new gateway IP address and I haven't seen any packet loss for 2+ hours compared to previous 2-5 outtages / hour.

 

So now I am more convinced that this was a case of a bad WAN gateway that Comcast owns.

 

I will update here if I see this problem comes back.

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1 Message

9 m ago

Having an extremely similar issue the past few weeks. Here it seems to come up during midday hours (2:00pm - 8:00pm central) where I will suddenly start having 30-60% of all my packets dropped. Causes tons of problems with any VPN or encrypted traffic while basic net surfing is generally fine if slow. It's definitely nothing on my side of the network because I have identical issues between two separate modems, internet lines, and computers; it's absolutely on Comcast's side. I've called customer service twice about the problem and all they do is tell me to update modems etc. etc. which has nothing to do with it. I'm convinced there's some network issue that affects service here in the midwest at certain times of day and I really wish they would address it.
scoobyblue

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13 Messages

9 m ago

How do you change your MAC address and where do you find another one to change it to? 

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6 Messages

9 m ago

I can second @mezzolan @shjin 's issues on my end using an XB7 in Houston.

Curious if @shjin has had a stable connection after changing the MAC on his bridged router?

EG

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86.5K Messages

9 m ago


@scoobyblue wrote:

How do you change your MAC address and where do you find another one to change it to? 


If you are using a Comcast supplied gateway device, you can't as they do not offer that feature. Only third party retail purchased devices have it.

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shjin

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5 Messages

9 m ago


@scoobyblue wrote:

How do you change your MAC address and where do you find another one to change it to? 


I am able to change it because I use xFi gateway as bridge mode (essentially acting as just a cable modem) and I use my own router (Unifi Security Gateway). Many consumer router have the feature to clone or change MAC address. 

 

I cloned my PC's MAC address as my WAN port's MAC address, but you can also generate it randomly.

101005-BS

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22 Messages

6 m ago

I agree the ping timeouts and sporadic packet loss are a comcast problem.Rebooted modem and router. No change. Reseated the coax connections outside my home. No change. I connected my laptop directly to the cable modem bypassing my router so I get a different ip address because the mac address changed. This helped a bit but still not 100%. The first hop in a traceroute is misleading. Your default gateway is your first hop which is the comcast network.

 

C:\>ping -t -w 150 71.196.40.1

Pinging 71.196.40.1 with 32 bytes of data:
Request timed out.
Reply from 71.196.40.1: bytes=32 time=10ms TTL=255
Reply from 71.196.40.1: bytes=32 time=11ms TTL=255
Reply from 71.196.40.1: bytes=32 time=11ms TTL=255
Request timed out.
Reply from 71.196.40.1: bytes=32 time=9ms TTL=255

 

Don't let a technician tell you to change the modem. The problem is not the modem or line. The comast internet is shared for the number of users in a given area, and a busier network will run heavy. My internet was great at my former home. This area is not as good. Yes, icmp (ping) is low priority, but udp and tcp are dropped as well. The packet loss affects my corporate vpn and voice.

 

But comcast does what is usually does, and they do it well. They sell services to make money. Technical support seems to be a lower priority.

 

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I've had this identical issue when running my Unifi Dream Machine Pro. Swapped out gateways and it fixed it for maybe a month, but the drops eventually came back. What's more interesting is that I can fix the issue entirely if I simply disable the bridge mode on my Xfi Gateway and run it as a full router (meaning I'm double nat'd yes, but I throw my real router into the DMZ on the Xfi gateway at least). As soon as bridge mode is disabled, all of the packet loss stops immediately. Someone on the Unifi forums claimed it was comcast intentionally prioritizing Xfi gateways being used in the way they wanted, vs throttling and giving poor QOS to the ones that sat in bridge. While I'll admit that seems fringe conspiracy, at the same time, given the results I'm seeing and my experience with Comcast over the past 10 years......I wouldn't put it past them......

EG

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86.5K Messages

20 d ago

8-month-old dead thread now being closed.

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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Was your question answered? Mark the post as Best Answer!tick

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