Why Sometimes I Can't Access Some Websites Through Cable Modem?

Boris_yo

Limp Gawd
Joined
Oct 22, 2011
Messages
224
Hello,

I am non-US and have issues connecting to some websites through my ISP's cable modem, be it wired connection or wireless.

However I have no such issue connecting through my cellular provider's 4G LTE internet.

In both cases I tried connecting from smartphone and laptop through wireless connection and from desktop computer using wired connection.I also tried different browsers on Android smartphone, laptop and desktopCleared cache and cookiesConnected wireless router to cable modem and connected to internet through it. Tried different DNS servers: Cloudflare, Google, NextDNS and all to no avail.

At worst case website loads too slow without displaying anything so I don't wait. At best case website loads but some elements are missing/not displayed. All that as long as it's through my ISP's cable modem.

Attached below are 3 screenshots.

On third screenshot is when I access the website through cellular operator's network and how it should be displayed.

On first screenshot is when I access the website through ISP's cable modem. It's missing elements like light-blue background and instead of warning sign icon shows text.

On second screenshot is when I access website through ISP's cable modem. It now shows light-blue background and warnibg sign icon but is still missing weather background and weather data.

Sometimes website is stuck loading too long on smartphone, laptop and desktop so I give up waiting.

Any idea what is going on?
 

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This is just normal with the type of Internet available in that part of the world with the 'take it or leave it' attitude that is what you get for customer service. (n)

The technical answer is that they probably have some routing or backbone issues or are filtering/pilfering the traffic, but that's also out of your control.
 
This can sometimes be caused by broken ICMP Path MTU Discovery. Either the cable modem or some other node is overzealous when filtering ICMP traffic.
Other explanation is broken IPv6.

Generally you should contact your ISP customer support and let them know of the issue and which websites are affected. They can tell whether it is an issue on their side or not.
 

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This can sometimes be caused by broken ICMP Path MTU Discovery. Either the cable modem or some other node is overzealous when filtering ICMP traffic.
Other explanation is broken IPv6.

Hello,

I used PingPlotter and see 100% packet loss on destination website however there are no other nodes with same issue.

Does that mean the issue is not ICMP path MTU Discovery but on destination website?

FB_IMG_1619625091469.jpg
 
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