Cisco Anyconnect connection established but trouble with some internet provider.

[Fast]

I am having a unusual issue.

Although  Anyconnect is able to establish a connection the user can't access the internal shared folders or navigate to internal intranet (with no errors). This is happening with an internet provider but not for example using the mobile connection or the same internet provider located in a different place. The user is using windows 10 PRO connected by wireless (speed 100mb). I am really surprised as because once the connection is established the internet provider can't interfere with it.  

What will be the best approach to solve it out?

Thanks

[Karsten Iwen]

Have you checked that the user is not using the same home network as you have your company resources in?

[Fast]

Do you mean network IP? The user home router is in a different LAN

[Mohammed al Baqari]

It might be that provider is not happy with your mtu and isn't allowing
fragmentation. Try to reduce anyconnect mtu from default (e.g. try 1260)
and see if works. Then you can increase gradually.

*** please remember to rate useful posts

[Fast]

The solution for this particular issue was disble ipv6 directly from the internet provider.

I was wondering, how did this thing solve the problem?

I am a bit confused.

Could someone explain me the reasons?

[Marvin Rhoads]

I've seen occasional issues where the IPv6 DNS service from the ISP doesn't successfully resolve the target VPN's IPv4 address.

I never resolved whether it was the provider DNS infrastructure or the IPv4-v6 middle box somewhere in their network but - just like your case - disabling IPv6 altogether fixed it.

[Fast]

Hi  Marvin,

could you please help me to understand better about this issue as It is not entirely clear for me.

How could the IPV6  interfere with the VPN once the tunnel is created and the connection is established?

[Fast]

Today I had a similar issue....with another ISP.

VPN connection established but not access to the shared folders, intranet etc.....

I could ping the server only by IP (so DNS issue)

This time I have disabled IPV6 on the network and VPN property and it seems worked.

I am very curious to understand what is behind this issue.

Thanks