ASA 5505 远程访问 VPN - 已建立连接，但没有互联网/访问内部子网

网络工程 思科 虚拟专用网
2021-07-30 19:35:59

更新

终于升级到9.1.4了。我配置了所有东西，重新启用了 VPN，但仍然遇到同样的问题。因此，我清除了所有 VPN 配置信息并从头开始。下面是我目前的配置。我能够连接和访问内部网络上的资源。但是，我无法通过 VPN 访问互联网。

xlate per-session deny tcp any4 any4
xlate per-session deny tcp any4 any6
xlate per-session deny tcp any6 any4
xlate per-session deny tcp any6 any6
xlate per-session deny udp any4 any4 eq domain
xlate per-session deny udp any4 any6 eq domain
xlate per-session deny udp any6 any4 eq domain
xlate per-session deny udp any6 any6 eq domain
ip local pool VPNPool 192.168.3.1-192.168.3.30
!
interface Ethernet0/0
 switchport access vlan 2
!
interface Ethernet0/1
 switchport access vlan 2
!
interface Ethernet0/2
 switchport access vlan 2
!
interface Ethernet0/3
!
interface Ethernet0/4
!
interface Ethernet0/5
!
interface Ethernet0/6
!
interface Ethernet0/7
!
interface Vlan1
 description Private-Interface
 nameif inside
 security-level 100
 ip address 10.3.3.1 255.255.255.0 
!
interface Vlan2
 description Public-Interface
 nameif outside
 security-level 0
 ip address xx.xx.xx.xx 255.255.255.248 
!
boot system disk0:/asa914-k8.bin
object network obj-10.3.3.0
 subnet 10.3.3.0 255.255.255.0
object network vpn_nat
 subnet 192.168.3.0 255.255.255.0
object-group service Internet-udp udp
 description UDP Standard Internet Services
 port-object eq domain
 port-object eq ntp
object-group service Internet-tcp tcp
 description TCP Standard Internet Services
 port-object eq www
 port-object eq https
 port-object eq smtp
 port-object eq 465
 port-object eq pop3
 port-object eq 995
 port-object eq ftp
 port-object eq ftp-data
 port-object eq domain
 port-object eq ssh
object-group network Internal-Subnet
object-group network obj-vpnpool
access-list inside-in remark -=[Access Lists for Outgoing Packets from Inside interface]=-
access-list inside-in extended permit udp 10.3.3.0 255.255.255.0 any4 object-group Internet-udp 
access-list inside-in extended permit tcp 10.3.3.0 255.255.255.0 any4 object-group Internet-tcp 
access-list inside-in extended permit icmp 10.3.3.0 255.255.255.0 any4 
access-list outside-in remark -=[Access Lists for Incoming Packets on OUTSIDE interface]=-
access-list outside-in extended permit icmp any4 any4 echo-reply 
access-list outside-in extended permit icmp any4 any4 echo 
access-list vpn_splitTunnelAcl standard permit 10.3.3.0 255.255.255.0 
nat (inside,outside) source static obj-10.3.3.0 obj-10.3.3.0 destination static vpn_nat vpn_nat no-proxy-arp route-lookup
object network obj-10.3.3.0
 nat (inside,outside) dynamic interface
access-group inside-in in interface inside
access-group outside-in in interface outside
route outside 0.0.0.0 0.0.0.0 xx.xx.xx.xx 1 
timeout xlate 3:00:00
timeout pat-xlate 0:00:30
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 
aaa authentication http console LOCAL 
aaa authentication ssh console LOCAL 
http server enable
http 10.3.3.0 255.255.255.0 inside
no snmp-server location
no snmp-server contact
snmp-server enable traps snmp authentication linkup linkdown coldstart
crypto ipsec ikev1 transform-set vpn-transform-set-ikev1 esp-3des esp-sha-hmac 
crypto ipsec ikev1 transform-set vpn-transform-set-ikev1 mode transport
crypto ipsec security-association pmtu-aging infinite
crypto dynamic-map dyno 10 set ikev1 transform-set vpn-transform-set-ikev1
crypto map vpn 20 ipsec-isakmp dynamic dyno
crypto map vpn interface outside
crypto ca trustpool policy
crypto isakmp nat-traversal 3600
crypto ikev1 enable outside
crypto ikev1 policy 10
 authentication pre-share
 encryption 3des
 hash sha
 group 2
 lifetime 86400
telnet timeout 5
ssh 10.3.3.0 255.255.255.0 inside
ssh timeout 20
ssh version 2
ssh key-exchange group dh-group1-sha1
console timeout 0



dhcpd address 10.3.3.100-10.3.3.150 inside
dhcpd dns xx.xx.xx.xx xx.xx.xx.xx interface inside
dhcpd enable inside
!
threat-detection basic-threat
threat-detection statistics host number-of-rate 2
threat-detection statistics port number-of-rate 2
threat-detection statistics protocol number-of-rate 2
threat-detection statistics access-list
no threat-detection statistics tcp-intercept
group-policy vpn_policy internal
group-policy vpn_policy attributes
 vpn-tunnel-protocol l2tp-ipsec 
 split-tunnel-policy tunnelspecified
 split-tunnel-network-list value vpn_splitTunnelAcl
username mike password x
username mike attributes
 vpn-tunnel-protocol l2tp-ipsec 
username admin password x encrypted privilege 15
tunnel-group DefaultRAGroup general-attributes
 address-pool VPNPool
 default-group-policy vpn_policy
tunnel-group DefaultRAGroup ipsec-attributes
 ikev1 pre-shared-key *
tunnel-group DefaultRAGroup ppp-attributes
 authentication ms-chap-v2
!
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 ip-options 
  inspect netbios 
  inspect rsh 
  inspect rtsp 
  inspect skinny

  inspect esmtp 
  inspect sqlnet 
  inspect sunrpc 
  inspect tftp 
  inspect sip

  inspect xdmcp 
 class class-default
  user-statistics accounting
!
service-policy global_policy global
prompt hostname context 
no call-home reporting anonymous
call-home
 profile CiscoTAC-1
  no active
  destination address http https://tools.cisco.com/its/service/oddce/services/DDCEService
  destination address email callhome@cisco.com
  destination transport-method http
  subscribe-to-alert-group diagnostic
  subscribe-to-alert-group environment
  subscribe-to-alert-group inventory periodic monthly
  subscribe-to-alert-group configuration periodic monthly
  subscribe-to-alert-group telemetry periodic daily
: end

老东西

我正在尝试在 ASA 5505 版本 8.2(5) 上设置 L2TP over IPSec 远程访问 VPN。我能够进行身份验证并建立连接。但是，我无法访问内部网络上的资源或访问 Internet。此外，ASA 无法 ping 连接的客户端。

在连接的客户端上，我可以 ping ASA 的外部 IP。当我这样做时，我什至看到加密和解密的数据包计数在 ASA 上以show crypto ipsec sa.

我试过用 NAT 和路由做一些事情，但就是无法让它工作。

我的内部网络是 10.3.3.0/24，我的 VPN 池是 192.168.3.0/24。下面我复制了配置的相关部分。


object-group service Internet-udp udp
 description UDP Standard Internet Services
 port-object eq domain
 port-object eq ntp
object-group service Internet-tcp tcp
 description TCP Standard Internet Services
 port-object eq www
 port-object eq https
 port-object eq smtp
 port-object eq 465
 port-object eq pop3
 port-object eq 995
 port-object eq ftp
 port-object eq ftp-data
 port-object eq domain
 port-object eq ssh
 port-object eq 993
object-group network Internal-Subnet
object-group network obj-vpnpool
access-list inside-in remark -=[Access Lists for Outgoing Packets from Inside interface]=-
access-list inside-in extended permit udp 10.3.3.0 255.255.255.0 any object-group Internet-udp
access-list inside-in extended permit tcp 10.3.3.0 255.255.255.0 any object-group Internet-tcp
access-list inside-in extended permit icmp 10.3.3.0 255.255.255.0 any
access-list outside-in remark -=[Access Lists for Incoming Packets on OUTSIDE interface]=-
access-list outside-in extended permit icmp any any echo-reply
access-list DefaultRAGroup_splitTunnelAcl standard permit 10.3.3.0 255.255.255.0
access-list DefaultRAGroup_splitTunnelAcl standard permit 192.168.3.96 255.255.255.224
access-list inside_nat0_outbound extended permit ip 10.3.3.0 255.255.255.0 192.168.3.0 255.255.255.0

ip local pool VPNPool 192.168.3.100-192.168.3.120 mask 255.255.255.0

nat (inside) 0 access-list inside_nat0_outbound
nat (inside) 1 10.3.3.0 255.255.255.0
access-group inside-in in interface inside
access-group outside-in in interface outside
route outside 0.0.0.0 0.0.0.0 **.**.**.** 1

group-policy DefaultRAGroup internal
group-policy DefaultRAGroup attributes
 dns-server value **.**.**.** **.**.**.**
 vpn-tunnel-protocol l2tp-ipsec
 split-tunnel-policy tunnelspecified
 split-tunnel-network-list value DefaultRAGroup_splitTunnelAcl

crypto ipsec transform-set ESP-AES-256-MD5 esp-aes-256 esp-md5-hmac 
crypto ipsec transform-set ESP-DES-SHA esp-des esp-sha-hmac 
crypto ipsec transform-set ESP-3DES-SHA esp-3des esp-sha-hmac 
crypto ipsec transform-set ESP-DES-MD5 esp-des esp-md5-hmac 
crypto ipsec transform-set ESP-AES-192-MD5 esp-aes-192 esp-md5-hmac 
crypto ipsec transform-set ESP-3DES-MD5 esp-3des esp-md5-hmac 
crypto ipsec transform-set ESP-AES-256-SHA esp-aes-256 esp-sha-hmac 
crypto ipsec transform-set ESP-AES-128-SHA esp-aes esp-sha-hmac 
crypto ipsec transform-set ESP-AES-192-SHA esp-aes-192 esp-sha-hmac 
crypto ipsec transform-set ESP-AES-128-MD5 esp-aes esp-md5-hmac 
crypto ipsec transform-set TRANS_ESP_3DES_SHA esp-3des esp-sha-hmac 
crypto ipsec transform-set TRANS_ESP_3DES_SHA mode transport
crypto ipsec security-association lifetime seconds 28800
crypto ipsec security-association lifetime kilobytes 4608000
crypto dynamic-map SYSTEM_DEFAULT_CRYPTO_MAP 65535 set transform-set TRANS_ESP_3DES_SHA 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 isakmp enable outside
crypto isakmp policy 10
 authentication pre-share
 encryption 3des
 hash sha     
 group 2
 lifetime 86400

更新 1

我接受了 Ron 的建议并了解了packet-tracer命令的功能。以下是我发布后发现的一些内容packet-tracer input inside icmp 10.3.3.100 8 0 192.168.3.100


Phase: 1
Type: ROUTE-LOOKUP
Subtype: input
Result: ALLOW
Config:
Additional Information:
in   192.168.3.100   255.255.255.255 outside

Phase: 2
Type: ACCESS-LIST
Subtype: log
Result: ALLOW
Config:
access-group inside-in in interface inside
access-list inside-in extended permit icmp 10.3.3.0 255.255.255.0 any 
Additional Information:

Phase: 3
Type: IP-OPTIONS
Subtype: 
Result: ALLOW
Config:
Additional Information:

Phase: 4      
Type: INSPECT 
Subtype: np-inspect
Result: ALLOW
Config:
Additional Information:

Phase: 5
Type: NAT-EXEMPT
Subtype: 
Result: ALLOW
Config:
  match ip inside 10.3.3.0 255.255.255.0 outside 192.168.3.0 255.255.255.0
    NAT exempt
    translate_hits = 16, untranslate_hits = 2
Additional Information:

Phase: 6
Type: NAT
Subtype: 
Result: ALLOW
Config:
nat (inside) 1 10.3.3.0 255.255.255.0
  match ip inside 10.3.3.0 255.255.255.0 outside any
    dynamic translation to pool 1 (**.**.**.** [Interface PAT])
    translate_hits = 21582, untranslate_hits = 2392
Additional Information:

Phase: 7
Type: NAT
Subtype: host-limits
Result: ALLOW
Config:
nat (inside) 1 10.3.3.0 255.255.255.0
  match ip inside 10.3.3.0 255.255.255.0 inside any
    dynamic translation to pool 1 (No matching global)
    translate_hits = 0, untranslate_hits = 0
Additional Information:

Phase: 8
Type: HOST-LIMIT
Subtype: 
Result: ALLOW
Config:
Additional Information:

Phase: 9
Type: L2TP-PPP
Subtype: 
Result: ALLOW 
Config:
Additional Information:

Phase: 10
Type: PPP
Subtype: 
Result: ALLOW
Config:
Additional Information:

Phase: 11
Type: FLOW-CREATION
Subtype: 
Result: ALLOW
Config:
Additional Information:
New flow created with id 23037, packet dispatched to next module

Result:
input-interface: inside
input-status: up
input-line-status: up
output-interface: outside
output-status: up
output-line-status: up
Action: allow

阶段 6 显示了 NAT 转换。然后我用packet-tracer input outside icmp 192.168.3.100 0 0 10.3.3.100.


Phase: 1
Type: ROUTE-LOOKUP
Subtype: input
Result: ALLOW
Config:
Additional Information:
in   10.3.3.0        255.255.255.0   inside

Phase: 2
Type: ACCESS-LIST
Subtype: log
Result: ALLOW
Config:
access-group outside-in in interface outside
access-list outside-in extended permit icmp any any echo-reply 
Additional Information:

Phase: 3
Type: IP-OPTIONS
Subtype: 
Result: ALLOW
Config:
Additional Information:

Phase: 4      
Type: CP-PUNT
Subtype: 
Result: ALLOW
Config:
Additional Information:

Phase: 5
Type: L2TP-PPP
Subtype: 
Result: ALLOW
Config:
Additional Information:

Phase: 6
Type: INSPECT
Subtype: np-inspect
Result: ALLOW
Config:
Additional Information:

Phase: 7
Type: VPN
Subtype: ipsec-tunnel-flow
Result: ALLOW 
Config:
Additional Information:

Phase: 8
Type: NAT-EXEMPT
Subtype: rpf-check
Result: ALLOW
Config:
Additional Information:

Phase: 9
Type: HOST-LIMIT
Subtype: 
Result: ALLOW
Config:
Additional Information:

Phase: 10
Type: NAT
Subtype: rpf-check
Result: ALLOW
Config:
nat (inside) 1 10.3.3.0 255.255.255.0
  match ip inside 10.3.3.0 255.255.255.0 outside any
    dynamic translation to pool 1 (**.**.**.** [Interface PAT])
    translate_hits = 21589, untranslate_hits = 2392
Additional Information:

Phase: 11
Type: FLOW-CREATION
Subtype: 
Result: ALLOW
Config:
Additional Information:
New flow created with id 23079, packet dispatched to next module

Result:
input-interface: outside
input-status: up
input-line-status: up
output-interface: inside
output-status: up
output-line-status: up
Action: allow

阶段 8 显示，NAT-EXEMPT但阶段 10 显示 NAT 转换。那将是有问题的。

更新 2

当前show vpn-sessiondb detail remote filter protocol L2TPOverIPSec连接客户端时不返回任何内容。

另一方面show vpn-sessiondb detail remote filter protocol L2TPOverIPSecOverNatT显示连接的客户端。尝试在客户端上执行操作时，Bytes Rx 和 Pkts Rx 会增加。Bytes Tx 和 Pkts Tx 不增加（Pkts Tx 保持在 17）。Pkts Tx Drop 和 Pkts Rx Drop 都是 0。如果我 ping 192.168.3.100（vpn 客户端），那么 Pkts Tx 会随着每次 ping 的增加而增加。

更新 3

我在 ASA 上启用了日志记录并建立了连接。这是我看到的一些有趣的日志消息


%ASA-6-737026: IPAA: Client assigned 192.168.3.100 from local pool
ppp_virtual_interface_id is 1, client_dynamic_ip is 192.168.3.100
%ASA-7-609001: Built local-host outside:192.168.3.100
%ASA-2-106001: Inbound TCP connection denied from 192.168.3.100/57013 to **.**.**.**/443 flags SYN  on interface outside
%ASA-2-106001: Inbound TCP connection denied from 192.168.3.100/57013 to **.**.**.**/443 flags SYN  on interface outside
%ASA-2-106001: Inbound TCP connection denied from 192.168.3.100/57013 to **.**.**.**/443 flags SYN  on interface outside
%ASA-2-106007: Deny inbound UDP from 192.168.3.100/9562 to **.**.**.**/53 due to DNS Query
%ASA-2-106007: Deny inbound UDP from 192.168.3.100/61529 to **.**.**.**/53 due to DNS Query
%ASA-2-106007: Deny inbound UDP from 192.168.3.100/38824 to **.**.**.**/53 due to DNS Query

%ASA-3-713042: IKE Initiator unable to find policy: Intf inside, Src: 10.3.3.100, Dst: 192.168.3.100
%ASA-3-713042: IKE Initiator unable to find policy: Intf inside, Src: 10.3.3.100, Dst: 192.168.3.100
4个回答

为了使客户端能够连接到 VPN 隧道之外的资源，必须配置拆分隧道。这将允许适配器继承它自己的路由表之外的路由，并允许流量流出。在连接时添加路由只是问题的一部分。

这是 ADM 和 CLI 说明的链接 http://www.cisco.com/c/en/us/support/docs/security/asa-5500-x-series-next-generation-firewalls/70917-asa -split-tunnel-vpn-client.html

所有的答案都暗示了一个拆分隧道，我相信我已经正确设置了。

最后，我在内部网络上设置了一个代理服务器。如果我的浏览器指向那个，那么我可以通过它访问互联网。

要访问互联网，您必须配置拆分隧道，因为拆分隧道定义了哪些流量将通过隧道传输，哪些不会，因为默认情况下所有流量都将通过隧道传输。您可以通过键入（打印路由）在您的计算机上看到所有流量都将通过隧道传输，如果您不想使用拆分隧道，那么我们还有一个解决方案，您可以配置反向网络，第一个数据包将发送到您的远程服务器和远程服务器将发送回互联网

我怀疑 L2TP over IPSec 可能不支持拆分隧道。你能帮我试试以下吗？

conf t
!
same-security-traffic permit intra-interface
!
object network vpn_nat
 nat (outside,outside) dynamic interface
!

我还注意到您更新的组策略中缺少 DNS 服务器配置。

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