Intermittent Internet Connection and VPN clients can't ping internal LAN but connected after installating cisco ASA5512x

Question

Hi!
I wish someone can help me on this, I'm a new guy on cisco firewalls and I'm currently implementing cisco asa 5512x, here are the details:
ISP ->  Firewall -> Core switch -> Internal LAN
after installing the cisco asa and terminating the appropriate lan for the outside and inside interfaces, internet seems intermittent and cisco vpn client can connect with internet connection but can't ping internal LAN.
here's my configuration from my firewall.
ASA Version 8.6(1)2
hostname ciscofirewall
enable password 2KFQnbNIdI.2KYOU encrypted
passwd 2KFQnbNIdI.2KYOU encrypted
names
interface GigabitEthernet0/0
nameif outside
security-level 0
ip address 203.x.x.x 255.255.255.0
interface GigabitEthernet0/1
nameif inside
security-level 100
ip address 10.152.11.15 255.255.255.0
interface GigabitEthernet0/2
shutdown
no nameif
no security-level
no ip address
interface GigabitEthernet0/3
shutdown
no nameif
no security-level
no ip address
interface GigabitEthernet0/4
shutdown
no nameif
no security-level
no ip address
interface GigabitEthernet0/5
shutdown
no nameif
no security-level
no ip address
interface Management0/0
nameif management
security-level 100
ip address 192.168.1.1 255.255.255.0
management-only
ftp mode passive
dns domain-lookup outside
dns domain-lookup inside
dns server-group DefaultDNS
name-server 4.2.2.2 -------> public DNS
name-server 8.8.8.8 -------> public
name-server 203.x.x.x   ----> Clients DNS
name-server 203.x.x.x  -----> Clients DNS
same-security-traffic permit intra-interface
object network net_access
subnet 10.0.0.0 255.0.0.0
object network citrix_server
host 10.152.11.21
object network NETWORK_OBJ_10.10.10.0_28
subnet 10.10.10.0 255.255.255.240
object network NETWORK_OBJ_10.0.0.0_8
subnet 10.0.0.0 255.0.0.0
object network InterconHotel
subnet 10.152.11.0 255.255.255.0
access-list net_surf extended permit ip any any
access-list net_surf extended permit ip object NETWORK_OBJ_10.10.10.0_28 object InterconHotel
access-list outside_access extended permit tcp any object citrix_server eq www
access-list outside_access extended permit ip object NETWORK_OBJ_10.10.10.0_28 any
access-list outsidevpn_splitTunnelAcl standard permit 10.152.11.0 255.255.255.0
access-list LAN_Users remark LAN_clients
access-list LAN_Users standard permit any
access-list vpnpool extended permit ip 10.10.10.0 255.255.255.248 any
pager lines 24
logging enable
logging asdm informational
mtu management 1500
mtu outside 1500
mtu inside 1500
ip local pool vpnpool 10.10.10.1-10.10.10.6 mask 255.255.255.248
icmp unreachable rate-limit 1 burst-size 1
no asdm history enable
arp timeout 14400
nat (inside,outside) source static NETWORK_OBJ_10.10.10.0_28 NETWORK_OBJ_10.10.10.0_28 destination static NETWORK_OBJ_10.10.10.0_28 NETWORK_OBJ_10.10.10.0_28 no-proxy-arp route-lookup
object network net_access
nat (inside,outside) dynamic interface
object network citrix_server
nat (inside,outside) static 203.177.18.234 service tcp www www
object network NETWORK_OBJ_10.10.10.0_28
nat (any,outside) dynamic interface
object network InterconHotel
nat (inside,outside) dynamic interface dns
access-group outside_access in interface outside
access-group net_surf out interface outside
route outside 0.0.0.0 0.0.0.0 203.x.x.x 1
route outside 10.10.10.0 255.255.255.248 10.152.11.15 1
timeout xlate 3:00:00
timeout conn 1:00:00 half-closed 0:10:00 udp 0:02:00 icmp 0:00:02
timeout sunrpc 0:10:00 h323 0:05:00 h225 1:00:00 mgcp 0:05:00 mgcp-pat 0:05:00
timeout sip 0:30:00 sip_media 0:02:00 sip-invite 0:03:00 sip-disconnect 0:02:00
timeout sip-provisional-media 0:02:00 uauth 0:05:00 absolute
timeout tcp-proxy-reassembly 0:01:00
timeout floating-conn 0:00:00
dynamic-access-policy-record DfltAccessPolicy
user-identity default-domain LOCAL
aaa authentication telnet console LOCAL
http server enable
http 192.168.1.0 255.255.255.0 management
http 10.0.0.100 255.255.255.255 inside
http 10.10.10.0 255.255.255.240 outside
http 0.0.0.0 0.0.0.0 outside
no snmp-server location
no snmp-server contact
snmp-server enable traps snmp authentication linkup linkdown coldstart warmstart
crypto ipsec ikev1 transform-set ESP-AES-256-MD5 esp-aes-256 esp-md5-hmac
crypto ipsec ikev1 transform-set ESP-DES-SHA esp-des esp-sha-hmac
crypto ipsec ikev1 transform-set ESP-3DES-SHA esp-3des esp-sha-hmac
crypto ipsec ikev1 transform-set ESP-DES-MD5 esp-des esp-md5-hmac
crypto ipsec ikev1 transform-set ESP-AES-192-MD5 esp-aes-192 esp-md5-hmac
crypto ipsec ikev1 transform-set ESP-3DES-MD5 esp-3des esp-md5-hmac
crypto ipsec ikev1 transform-set ESP-AES-256-SHA esp-aes-256 esp-sha-hmac
crypto ipsec ikev1 transform-set ESP-AES-128-SHA esp-aes esp-sha-hmac
crypto ipsec ikev1 transform-set ESP-AES-192-SHA esp-aes-192 esp-sha-hmac
crypto ipsec ikev1 transform-set ESP-AES-128-MD5 esp-aes esp-md5-hmac
crypto dynamic-map SYSTEM_DEFAULT_CRYPTO_MAP 65535 set pfs
crypto dynamic-map SYSTEM_DEFAULT_CRYPTO_MAP 65535 set ikev1 transform-set ESP-AES-128-SHA ESP-AES-128-MD5 ESP-AES-192-SHA ESP-AES-192-MD5 ESP-AES-256-SHA ESP-AES-256-MD5 ESP-3DES-SHA ESP-3DES-MD5 ESP-DES-SHA ESP-DES-MD5
crypto map outside_map 65535 ipsec-isakmp dynamic SYSTEM_DEFAULT_CRYPTO_MAP
crypto map outside_map interface outside
crypto map inside_map 65535 ipsec-isakmp dynamic SYSTEM_DEFAULT_CRYPTO_MAP
crypto map inside_map interface inside
crypto ikev1 enable outside
crypto ikev1 enable inside
crypto ikev1 policy 10
authentication crack
encryption aes-256
hash sha
group 2
lifetime 86400
crypto ikev1 policy 20
authentication rsa-sig
encryption aes-256
hash sha
group 2
lifetime 86400
crypto ikev1 policy 30
authentication pre-share
encryption aes-256
hash sha
group 2
lifetime 86400
crypto ikev1 policy 40
authentication crack
encryption aes-192
hash sha
group 2
lifetime 86400
crypto ikev1 policy 50
authentication rsa-sig
encryption aes-192
hash sha
group 2
lifetime 86400
crypto ikev1 policy 60
authentication pre-share
encryption aes-192
hash sha
group 2
lifetime 86400
crypto ikev1 policy 70
authentication crack
encryption aes
hash sha
group 2
lifetime 86400
crypto ikev1 policy 80
authentication rsa-sig
encryption aes
hash sha
group 2
lifetime 86400
crypto ikev1 policy 90
authentication pre-share
encryption aes
hash sha
group 2
lifetime 86400
crypto ikev1 policy 100
authentication crack
encryption 3des
hash sha
group 2
lifetime 86400
crypto ikev1 policy 110
authentication rsa-sig
encryption 3des
hash sha
group 2
lifetime 86400
crypto ikev1 policy 120
authentication pre-share
encryption 3des
hash sha
group 2
lifetime 86400
crypto ikev1 policy 130
authentication crack
encryption des
hash sha
group 2
lifetime 86400
crypto ikev1 policy 140
authentication rsa-sig
encryption des
hash sha
group 2
lifetime 86400
crypto ikev1 policy 150
authentication pre-share
encryption des
hash sha
group 2
lifetime 86400
client-update enable
telnet 10.152.11.0 255.255.255.0 inside
telnet timeout 5
ssh timeout 5
console timeout 0
dhcpd address 192.168.1.2-192.168.1.254 management
dhcpd enable management
threat-detection basic-threat
threat-detection statistics
threat-detection statistics tcp-intercept rate-interval 30 burst-rate 400 average-rate 200
webvpn
enable outside
anyconnect-essentials
group-policy outsidevpn internal
group-policy outsidevpn attributes
dns-server value 203.x.x.x 203.x.x.x
vpn-tunnel-protocol ikev1 l2tp-ipsec ssl-client
split-tunnel-policy tunnelall
split-tunnel-network-list value outsidevpn_splitTunnelAcl
default-domain value interconti.com
address-pools value vpnpool
username test1 password i1lji/GiOWB67bAs encrypted privilege 5
username test1 attributes
vpn-group-policy outsidevpn
username mnlha password WlzjmENGEEZmT9LA encrypted
username mnlha attributes
vpn-group-policy outsidevpn
username cisco password 3USUcOPFUiMCO4Jk encrypted privilege 15
tunnel-group outsidevpn type remote-access
tunnel-group outsidevpn general-attributes
address-pool (inside) vpnpool
address-pool vpnpool
authentication-server-group (outside) LOCAL
default-group-policy outsidevpn
tunnel-group outsidevpn ipsec-attributes
ikev1 pre-shared-key *****
class-map inspection_default
match default-inspection-traffic
policy-map type inspect dns preset_dns_map
parameters
  message-length maximum client auto
  message-length maximum 512
policy-map global_policy
class inspection_default
  inspect dns preset_dns_map
  inspect ftp
  inspect h323 h225
  inspect h323 ras
  inspect rsh
  inspect rtsp
  inspect esmtp
  inspect sqlnet
  inspect skinny 
  inspect sunrpc
  inspect xdmcp
  inspect sip 
  inspect netbios
  inspect tftp
  inspect ip-options
  inspect icmp
  inspect http
  inspect ipsec-pass-thru
class class-default
  user-statistics accounting
service-policy global_policy global
prompt hostname context
no call-home reporting anonymous
hpm topN enable
Cryptochecksum:edc30dda08e5800fc35b72dd6e1d88d7
: end
thanks. please help.

Answer 1

I think you should change your nat-exemption rule to smth more general, like
nat (inside,outside) source static any any destination static NETWORK_OBJ_10.10.10.0_28  NETWORK_OBJ_10.10.10.0_28 no-proxy-arp route-lookup
'cause your inside networks are not the same as your vpn-pool subnet.
Plus, if you're trying to reach inside subnets, different from 10.152.11.0 255.255.255.0 (ip from wich subnet is assignet to your inside interface, and for wich above nat exception should be enough), you should check if routing is configured from that subnets to your vpn-pool-subnet through the ASA.