Cisco 1811 - VPN clients receive DNS from external DHCP interface, how to disable?

Question

Domain Name System

Good afternoon!
There are 2 providers, one is configured by statics, the second receives settings on DHCP.
DNS servers are specified in the Cisco configuration:

ip name-server 192.168.0.151
ip name-server 8.8.8.8

Also, in the interface settings, I disabled receiving DNS via DHCP:

interface FastEthernet1
 description internet-outside-ISP2
 no ip dhcp client request dns-nameserver
 ip address dhcp
 ip nat outside
 ip virtual-reassembly
 duplex auto
 speed auto

However, VPN clients from somewhere take DNS issued by this provider via DHCP.
Because this provider is used as a backup, and its DNS servers are only accessible from under its subnets, users have a problem with name resolution.

Answer 1

Anatoly , you can add an explicit reference to the dns server to the configuration:
crypto isakmp client configuration group yyy
dns xxxx

Answer 2

Rinat Garipov thanks for the answer, this group has such a setting.
Sorry for not clarifying, the issue occurs with the vpdn-group vpnaccess group:

vpdn-group vpnaccess
! Default PPTP VPDN group
 accept-dialin
  protocol pptp
  virtual-template 100
 l2tp tunnel receive-window 256

interface Virtual-Template100
 ip unnumbered FastEthernet0
 ip broadcast-address 192.168.0.255
 ip nat inside
 ip virtual-reassembly
 peer default ip address pool DIAL-IN
 ppp encrypt mppe auto required
 ppp bridge ip
 ppp authentication ms-chap ms-chap-v2

Is it possible to prescribe this kind of setting there?
Full configuration here: pastebin.com/s3243khJ