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本文档介绍如何在思科自适应安全设备上实施网络地址转换(NAT)反射配置,以满足需要在防火墙上进行此类NAT配置的特殊Cisco TelePresence场景。
Cisco 建议您了解以下主题:
Cisco ASA(自适应安全设备)基本NAT配置。
Cisco TelePresence Video Communication Server(VCS)Control和VCS Expressway基本配置。
注意:本文档旨在仅在不能使用具有不同DMZ中的两个NIC接口的VCS-Expressway或Expressway-Edge的推荐部署方法时使用。有关建议使用双NIC进行部署的详细信息,请查看以下链接(位于第60页):“Cisco TelePresence Video Communication Server Basic Configuration(Control with Expressway)Deployment Guide”(思科网真视频通信服务器基本配置(使用Expressway进行控制)部署指南)
本文档中的信息基于以下软件和硬件版本:
运行软件版本8.3及更高版本的Cisco ASA 5500和5500-X系列设备。
Cisco VCS版本X8.x及更高版本。
本文档中的信息都是基于特定实验室环境中的设备编写的。本文档中使用的所有设备最初均采用原始(默认)配置。如果您使用的是真实网络,请确保您已经了解所有命令的潜在影响。
注意:在整个文档中,VCS设备称为VCS Expressway和VCS Control。但是,相同配置适用于Expressway-E和Expressway-C设备。
根据Cisco TelePresence文档,有两种类型的网真场景,需要在防火墙上进行NAT反射配置,以允许VCS Control通过VCS Expressway公有IP地址与VCS Expressway通信。
第一个场景涉及使用单个VCS Expressway LAN接口的单个子网非军事化区域(DMZ),第二个场景涉及使用单个VCS Expressway LAN接口的3端口FW DMZ。
提示:要了解有关网真实施的更多详细信息,请参阅思科网真视频通信服务器基本配置(使用Expressway控制)部署指南。
请务必注意,思科不推荐以下拓扑。VCS Expressway或Expressway边缘的推荐部署方法是:使用两个不同的DMZ,并且Expressway在每个DMZ中都有一个NIC。本指南适用于无法使用推荐部署方法的环境。
在此场景中,防火墙A可以将流量路由到防火墙B(反之亦然)。 VCS Expressway允许视频流量通过FW B,而不会减少FW B上从外部到内部接口的流量。VCS Expressway还在其公共端处理FW遍历。
以下是此方案的示例:

此部署使用以下组件:
FW A上已配置静态的一对一NAT,该NAT将公有地址64.100.0.10执行到VCS Expressway的LAN1 IP地址的NAT。VCS Expressway上的LAN1接口已启用静态NAT模式,静态NAT IP地址为64.100.0.10。
注意:您必须输入VCS Control安全遍历客户端区域(对等体地址)上VCS Expressway的完全限定域名(FQDN),就像从网络外部看到的那样。原因是在静态NAT模式下,VCS Expressway请求将入站信令和媒体流量发送到其外部FQDN而不是其专用名称。这也意味着外部FW必须允许从VCS Control到VCS Expressway外部FQDN的流量。这称为NAT反射,所有类型的防火墙可能都不支持。
在本示例中,FW B必须允许来自VCS Control且目的地为VCS Expressway的外部IP地址(64.100.0.10)的流量的NAT反射。VCS Control上的遍历区域必须将64.100.0.10作为对等体地址(在FQDN到IP转换之后)。
VCS Expressway应配置默认网关10.0.10.1。此场景中是否需要静态路由取决于FW A和FW B的功能和设置。从VCS Control到VCS Expressway的通信通过VCS Expressway的64.100.0.10 IP地址进行;从VCS Expressway到VCS Control的返回流量可能必须通过默认网关。
VCS Expressway可以添加到IP地址为10.0.10.3(或IP地址为64.100.0.10,如果FW B允许这样做)的Cisco TMS,因为思科TMS管理通信不会受到VCS Expressway上的静态NAT模式设置的影响。
以下是此方案的示例:

在此部署中,使用3端口防火墙以创建:
FW A上已配置静态一对一NAT,它执行从VCS Expressway的公有IP地址64.100.0.10到LAN1 IP地址的NAT。VCS Expressway上的LAN1接口已启用静态NAT模式,静态NAT IP地址为64.100.0.10。
VCS Expressway应配置默认网关10.0.10.1。由于此网关必须用于离开VCS Expressway的所有流量,因此这种部署类型不需要静态路由。
VCS Control上的遍历客户端区域必须配置一个与VCS Expressway的静态NAT地址(本例中为64.100.0.10)匹配的对等地址,原因与前一场景中所述的原因相同。
注意:这意味着FW A必须允许来自目标IP地址为64.100.0.10的VCS Control的流量。这也称为NAT反射,应该注意的是,并非所有类型的防火墙都支持此功能。
VCS Expressway可以添加IP地址为10.0.10.2(或IP地址为64.100.0.10,如果FW A允许),因为思科TMS管理通信不会受到VCS Expressway上的静态NAT模式设置的影响。
本节介绍如何为两个不同的VCS C和E实施方案在ASA中配置NAT反射。
对于第一个场景,必须在FW A上应用此NAT反射配置,以允许从VCS控制(10.0.30.2)发往VCS Expressway的外部IP地址(64.100.0.10)的通信:

在本示例中,VCS控制IP地址为10.0.30.2/24,而VCS Expressway IP地址为10.0.10.3/24。
如果您假设在查找目标IP地址为64.100.0.10的VCS Expressway时,VCS控制IP地址10.0.30.2从FW B的内部接口移动到外部接口时仍保留,则您应在FW B上实施的NAT反射配置如下例所示。
ASA版本8.3及更高版本的示例:
object network obj-10.0.30.2
host 10.0.30.2
object network obj-10.0.10.3
host 10.0.10.3
object network obj-64.100.0.10
host 64.100.0.10
nat (inside,outside) source static obj-10.0.30.2 obj-10.0.30.2 destination static
obj-64.100.0.10 obj-10.0.10.3
NOTE: After this NAT is applied in the ASA you will receive a warning message as the following:
WARNING: All traffic destined to the IP address of the outside interface is being redirected.
WARNING: Users may not be able to access any service enabled on the outside interface.
ASA版本8.2及更早版本的示例:
access-list IN-OUT-INTERFACE extended permit ip host 10.0.30.2 host 64.100.0.10
static (inside,outside) 10.0.30.2 access-list IN-OUT-INTERFACE
access-list OUT-IN-INTERFACE extended permit ip host 10.0.10.3 host 10.0.30.2
static (outside,inside) 64.100.0.10 access-list OUT-IN-INTERFACE
注意:此NAT反射配置的主要目标是允许VCS控制能够到达VCS Expressway,但使用VCS Expressway公有IP地址而不是私有IP地址。如果在此NAT转换期间,VCS控制的源IP地址使用两次NAT配置而不是刚才所示的建议NAT配置进行更改,导致VCS Expressway看到来自其自身公有IP地址的流量,则MRA设备的电话服务不会启动。根据下面建议部分的第3部分,这不是支持的部署。
对于第二个场景,您必须在FW A上应用此NAT反射配置,以允许对来自VCS控制10.0.30.2的入站流量进行NAT反射,该入站流量指向VCS Expressway的外部IP地址(64.100.0.10):

在本示例中,VCS控制IP地址为10.0.30.2/24,而VCS Expressway IP地址为10.0.10.2/24。
如果您假设在查找目标IP地址为64.100.0.10的VCS Expressway时,VCS控制IP地址10.0.30.2从FW A的内部移动到DMZ接口时仍保留,则您应在FW A上实施的NAT反射配置如下例所示。
ASA版本8.3及更高版本的示例:
object network obj-10.0.30.2
host 10.0.30.2
object network obj-10.0.10.2
host 10.0.10.2
object network obj-64.100.0.10
host 64.100.0.10
nat (inside,DMZ) source static obj-10.0.30.2 obj-10.0.30.2 destination static
obj-64.100.0.10 obj-10.0.10.2
NOTE: After this NAT is applied you will receive a warning message as the following:
WARNING: All traffic destined to the IP address of the DMZ interface is being redirected.
WARNING: Users may not be able to access any service enabled on the DMZ interface.
ASA版本8.2及更早版本的示例:
access-list IN-DMZ-INTERFACE extended permit ip host 10.0.30.2 host 64.100.0.10
static (inside,DMZ) 10.0.30.2 access-list IN-DMZ-INTERFACE
access-list DMZ-IN-INTERFACE extended permit ip host 10.0.10.2 host 10.0.30.2
static (DMZ,inside) 64.100.0.10 access-list DMZ-IN-INTERFACE
注意:此NAT反射配置的主要目标是允许VCS控制能够到达VCS Expressway,但使用VCS Expressway公有IP地址而非私有IP地址。如果VCS控制的源IP地址在此NAT转换期间使用两次NAT配置而不是刚才所示的建议NAT配置进行了更改,导致VCS Expressway看到来自其自己的公有IP地址的流量,则MRA设备的电话服务不会出现。根据下面建议部分的第3部分,这不是支持的部署。
本部分提供您在ASA中看到的Packet Tracer输出,以确认NAT反射配置可根据需要在VCS C和E实施场景中运行。
以下是ASA版本8.3及更高版本的FW B Packet Tracer输出:
FW-B# packet-tracer input inside tcp 10.0.30.2 1234 64.100.0.10 80
Phase: 1
Type: UN-NAT
Subtype: static
Result: ALLOW
Config:
nat (inside,outside) source static obj-10.0.30.2 obj-10.0.30.2 destination
static obj-64.100.0.10 obj-10.0.10.3
Additional Information:
NAT divert to egress interface outside
Untranslate 64.100.0.10/80 to 10.0.10.3/80
Phase: 2
Type: IP-OPTIONS
Subtype:
Result: ALLOW
Config:
Additional Information:
Phase: 3
Type: NAT
Subtype:
Result: ALLOW
Config:
nat (inside,outside) source static obj-10.0.30.2 obj-10.0.30.2 destination
static obj-64.100.0.10 obj-10.0.10.3
Additional Information:
Static translate 10.0.30.2/1234 to 10.0.30.2/1234
Phase: 4
Type: NAT
Subtype: rpf-check
Result: ALLOW
Config:
nat (inside,outside) source static obj-10.0.30.2 obj-10.0.30.2 destination
static obj-64.100.0.10 obj-10.0.10.3
Additional Information:
Phase: 5
Type: IP-OPTIONS
Subtype:
Result: ALLOW
Config:
Additional Information:
Phase: 6
Type: FLOW-CREATION
Subtype:
Result: ALLOW
Config:
Additional Information:
New flow created with id 2, 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
以下是ASA版本8.2及更低版本的FW B Packet Tracer输出:
FW-B# packet-tracer input inside tcp 10.0.30.2 1234 64.100.0.10 80
Phase: 1
Type: UN-NAT
Subtype: static
Result: ALLOW
Config:
static (outside,inside) 64.100.0.10 access-list OUT-IN-INTERFACE
match ip outside host 10.0.10.3 inside host 10.0.30.2
static translation to 64.100.0.10
translate_hits = 0, untranslate_hits = 2
Additional Information:
NAT divert to egress interface outside
Untranslate 64.100.0.10/0 to 10.0.10.3/0 using netmask 255.255.255.255
Phase: 2
Type: IP-OPTIONS
Subtype:
Result: ALLOW
Config:
Additional Information:
Phase: 3
Type: NAT
Subtype:
Result: ALLOW
Config:
static (inside,outside) 10.0.30.2 access-list IN-OUT-INTERFACE
match ip inside host 10.0.30.2 outside host 64.100.0.10
static translation to 10.0.30.2
translate_hits = 1, untranslate_hits = 0
Additional Information:
Static translate 10.0.30.2/0 to 10.0.30.2/0 using netmask 255.255.255.255
Phase: 4
Type: NAT
Subtype: host-limits
Result: ALLOW
Config:
static (inside,outside) 10.0.30.2 access-list IN-OUT-INTERFACE
match ip inside host 10.0.30.2 outside host 64.100.0.10
static translation to 10.0.30.2
translate_hits = 1, untranslate_hits = 0
Additional Information:
Phase: 5
Type: NAT
Subtype: rpf-check
Result: ALLOW
Config:
static (outside,inside) 64.100.0.10 access-list OUT-IN-INTERFACE
match ip outside host 10.0.10.3 inside host 10.0.30.2
static translation to 64.100.0.10
translate_hits = 0, untranslate_hits = 2
Additional Information:
Phase: 6
Type: NAT
Subtype: host-limits
Result: ALLOW
Config:
static (outside,inside) 64.100.0.10 access-list OUT-IN-INTERFACE
match ip outside host 10.0.10.3 inside host 10.0.30.2
static translation to 64.100.0.10
translate_hits = 0, untranslate_hits = 2
Additional Information:
Phase: 7
Type: IP-OPTIONS
Subtype:
Result: ALLOW
Config:
Additional Information:
Phase: 8
Type: FLOW-CREATION
Subtype:
Result: ALLOW
Config:
Additional Information:
New flow created with id 1166, 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
以下是ASA版本8.3及更高版本的FW A Packet Tracer输出:
FW-A# packet-tracer input inside tcp 10.0.30.2 1234 64.100.0.10 80
Phase: 1
Type: UN-NAT
Subtype: static
Result: ALLOW
Config:
nat (inside,DMZ) source static obj-10.0.30.2 obj-10.0.30.2 destination
static obj-64.100.0.10 obj-10.0.10.2
Additional Information:
NAT divert to egress interface DMZ
Untranslate 64.100.0.10/80 to 10.0.10.2/80
Phase: 2
Type: IP-OPTIONS
Subtype:
Result: ALLOW
Config:
Additional Information:
Phase: 3
Type: NAT
Subtype:
Result: ALLOW
Config:
nat (inside,DMZ) source static obj-10.0.30.2 obj-10.0.30.2 destination
static obj-64.100.0.10 obj-10.0.10.2
Additional Information:
Static translate 10.0.30.2/1234 to 10.0.30.2/1234
Phase: 4
Type: NAT
Subtype: rpf-check
Result: ALLOW
Config:
nat (inside,DMZ) source static obj-10.0.30.2 obj-10.0.30.2 destination
static obj-64.100.0.10 obj-10.0.10.2
Additional Information:
Phase: 5
Type: IP-OPTIONS
Subtype:
Result: ALLOW
Config:
Additional Information:
Phase: 6
Type: FLOW-CREATION
Subtype:
Result: ALLOW
Config:
Additional Information:
New flow created with id 7, packet dispatched to next module
Result:
input-interface: inside
input-status: up
input-line-status: up
output-interface: DMZ
output-status: up
output-line-status: up
Action: allow
以下是ASA版本8.2及更低版本的FW A Packet Tracer输出:
FW-A# packet-tracer input inside tcp 10.0.30.2 1234 64.100.0.10 80
Phase: 1
Type: UN-NAT
Subtype: static
Result: ALLOW
Config:
static (DMZ,inside) 64.100.0.10 access-list OUT-IN-INTERFACE
match ip DMZ host 10.0.10.2 inside host 10.0.30.2
static translation to 64.100.0.10
translate_hits = 0, untranslate_hits = 2
Additional Information:
NAT divert to egress interface DMZ
Untranslate 64.100.0.10/0 to 10.0.10.2/0 using netmask 255.255.255.255
Phase: 2
Type: IP-OPTIONS
Subtype:
Result: ALLOW
Config:
Additional Information:
Phase: 3
Type: NAT
Subtype:
Result: ALLOW
Config:
static (inside,DMZ) 10.0.30.2 access-list IN-OUT-INTERFACE
match ip inside host 10.0.30.2 DMZ host 64.100.0.10
static translation to 10.0.30.2
translate_hits = 1, untranslate_hits = 0
Additional Information:
Static translate 10.0.30.2/0 to 10.0.30.2/0 using netmask 255.255.255.255
Phase: 4
Type: NAT
Subtype: host-limits
Result: ALLOW
Config:
static (inside,DMZ) 10.0.30.2 access-list IN-OUT-INTERFACE
match ip inside host 10.0.30.2 DMZ host 64.100.0.10
static translation to 10.0.30.2
translate_hits = 1, untranslate_hits = 0
Additional Information:
Phase: 5
Type: NAT
Subtype: rpf-check
Result: ALLOW
Config:
static (DMZ,inside) 64.100.0.10 access-list OUT-IN-INTERFACE
match ip DMZ host 10.0.10.2 inside host 10.0.30.2
static translation to 64.100.0.10
translate_hits = 0, untranslate_hits = 2
Additional Information:
Phase: 6
Type: NAT
Subtype: host-limits
Result: ALLOW
Config:
static (DMZ,inside) 64.100.0.10 access-list OUT-IN-INTERFACE
match ip DMZ host 10.0.10.2 inside host 10.0.30.2
static translation to 64.100.0.10
translate_hits = 0, untranslate_hits = 2
Additional Information:
Phase: 7
Type: IP-OPTIONS
Subtype:
Result: ALLOW
Config:
Additional Information:
Phase: 8
Type: FLOW-CREATION
Subtype:
Result: ALLOW
Config:
Additional Information:
New flow created with id 1166, packet dispatched to next module
Result:
input-interface: inside
input-status: up
input-line-status: up
output-interface: DMZ
output-status: up
output-line-status: up
Action: allow
您可以在ASA接口上配置数据包捕获,以便在数据包进入和离开所涉及的FW接口时确认NAT转换。
FW-A# sh cap capture capin type raw-data interface inside [Capturing - 5735 bytes] match ip host 10.0.30.2 host 64.100.0.10 capture capdmz type raw-data interface DMZ [Capturing - 5735 bytes] match ip host 10.0.10.2 host 10.0.30.2 FW-A# sh cap capin 71 packets captured 1: 22:21:37.095270 10.0.30.2 > 64.100.0.10: icmp: echo request 2: 22:21:37.100672 64.100.0.10 > 10.0.30.2: icmp: echo reply 3: 22:21:37.101313 10.0.30.2 > 64.100.0.10: icmp: echo request 4: 22:21:37.114373 64.100.0.10 > 10.0.30.2: icmp: echo reply 5: 22:21:37.157371 10.0.30.2 > 64.100.0.10: icmp: echo request 6: 22:21:37.174429 64.100.0.10 > 10.0.30.2: icmp: echo reply 7: 22:21:39.234164 10.0.30.2 > 64.100.0.10: icmp: echo request 8: 22:21:39.238528 64.100.0.10 > 10.0.30.2: icmp: echo reply 9: 22:21:39.261110 10.0.30.2 > 64.100.0.10: icmp: echo request 10: 22:21:39.270234 64.100.0.10 > 10.0.30.2: icmp: echo reply 11: 22:21:47.170614 10.0.30.2.38953 > 64.100.0.10.23: S 1841210281:1841210281(0)
win 4128 <mss 536> 12: 22:21:47.198933 64.100.0.10.23 > 10.0.30.2.38953: S 3354834096:3354834096(0)
ack 1841210282 win 4128 <mss 536> 13: 22:21:47.235186 10.0.30.2.38953 > 64.100.0.10.23: . ack 3354834097
win 4128 14: 22:21:47.242815 64.100.0.10.23 > 10.0.30.2.38953: P 3354834097:3354834109(12)
ack 1841210282 win 4128 15: 22:21:47.243014 10.0.30.2.38953 > 64.100.0.10.23: P 1841210282:1841210294(12)
ack 3354834097 win 4128 16: 22:21:47.243258 10.0.30.2.38953 > 64.100.0.10.23: . ack 3354834097
win 4128 17: 22:21:47.261094 64.100.0.10.23 > 10.0.30.2.38953: P 3354834109:3354834151(42)
ack 1841210282 win 4128 18: 22:21:47.280411 64.100.0.10.23 > 10.0.30.2.38953: P 3354834151:3354834154(3)
ack 1841210294 win 4116 19: 22:21:47.280625 64.100.0.10.23 > 10.0.30.2.38953: P 3354834154:3354834157(3)
ack 1841210294 win 4116 20: 22:21:47.280838 64.100.0.10.23 > 10.0.30.2.38953: P 3354834157:3354834163(6)
ack 1841210294 win 4116 21: 22:21:47.281082 10.0.30.2.38953 > 64.100.0.10.23: P 1841210294:1841210297(3)
ack 3354834109 win 4116 22: 22:21:47.281296 10.0.30.2.38953 > 64.100.0.10.23: P 1841210297:1841210300(3)
ack 3354834109 win 4116
FW-A# sh cap capdmz 71 packets captured 1: 22:21:37.095621 10.0.30.2 > 10.0.10.2: icmp: echo request 2: 22:21:37.100626 10.0.10.2 > 10.0.30.2: icmp: echo reply 3: 22:21:37.101343 10.0.30.2 > 10.0.10.2: icmp: echo request 4: 22:21:37.114297 10.0.10.2 > 10.0.30.2: icmp: echo reply 5: 22:21:37.157920 10.0.30.2 > 10.0.10.2: icmp: echo request 6: 22:21:37.174353 10.0.10.2 > 10.0.30.2: icmp: echo reply 7: 22:21:39.234713 10.0.30.2 > 10.0.10.2: icmp: echo request 8: 22:21:39.238452 10.0.10.2 > 10.0.30.2: icmp: echo reply 9: 22:21:39.261659 10.0.30.2 > 10.0.10.2: icmp: echo request 10: 22:21:39.270158 10.0.10.2 > 10.0.30.2: icmp: echo reply 11: 22:21:47.170950 10.0.30.2.38953 > 10.0.10.2.23: S 2196345248:2196345248(0)
win 4128 <mss 536> 12: 22:21:47.198903 10.0.10.2.23 > 10.0.30.2.38953: S 1814294604:1814294604(0)
ack 2196345249 win 4128 <mss 536> 13: 22:21:47.235263 10.0.30.2.38953 > 10.0.10.2.23: . ack 1814294605 win 4128 14: 22:21:47.242754 10.0.10.2.23 > 10.0.30.2.38953: P 1814294605:1814294617(12)
ack 2196345249 win 4128 15: 22:21:47.243105 10.0.30.2.38953 > 10.0.10.2.23: P 2196345249:2196345261(12)
ack 1814294605 win 4128 16: 22:21:47.243319 10.0.30.2.38953 > 10.0.10.2.23: . ack 1814294605 win 4128 17: 22:21:47.260988 10.0.10.2.23 > 10.0.30.2.38953: P 1814294617:1814294659(42)
ack 2196345249 win 4128 18: 22:21:47.280335 10.0.10.2.23 > 10.0.30.2.38953: P 1814294659:1814294662(3)
ack 2196345261 win 4116 19: 22:21:47.280564 10.0.10.2.23 > 10.0.30.2.38953: P 1814294662:1814294665(3)
ack 2196345261 win 4116 20: 22:21:47.280777 10.0.10.2.23 > 10.0.30.2.38953: P 1814294665:1814294671(6)
ack 2196345261 win 4116 21: 22:21:47.281143 10.0.30.2.38953 > 10.0.10.2.23: P 2196345261:2196345264(3)
ack 1814294617 win 4116 22: 22:21:47.281357 10.0.30.2.38953 > 10.0.10.2.23: P 2196345264:2196345267(3)
ack 1814294617 win 4116
FW-B# sh cap capture capin type raw-data interface inside [Capturing - 5815 bytes] match ip host 10.0.30.2 host 64.100.0.10 capture capout type raw-data interface outside [Capturing - 5815 bytes] match ip host 10.0.10.3 host 10.0.30.2 FW-B# sh cap capin 72 packets captured 1: 22:30:06.783681 10.0.30.2 > 64.100.0.10: icmp: echo request 2: 22:30:06.847856 64.100.0.10 > 10.0.30.2: icmp: echo reply 3: 22:30:06.877624 10.0.30.2 > 64.100.0.10: icmp: echo request 4: 22:30:06.900710 64.100.0.10 > 10.0.30.2: icmp: echo reply 5: 22:30:06.971598 10.0.30.2 > 64.100.0.10: icmp: echo request 6: 22:30:06.999551 64.100.0.10 > 10.0.30.2: icmp: echo reply 7: 22:30:07.075649 10.0.30.2 > 64.100.0.10: icmp: echo request 8: 22:30:07.134499 64.100.0.10 > 10.0.30.2: icmp: echo reply 9: 22:30:07.156409 10.0.30.2 > 64.100.0.10: icmp: echo request 10: 22:30:07.177496 64.100.0.10 > 10.0.30.2: icmp: echo reply 11: 22:30:13.802525 10.0.30.2.41596 > 64.100.0.10.23: S 1119515693:1119515693(0)
win 4128 <mss 536> 12: 22:30:13.861100 64.100.0.10.23 > 10.0.30.2.41596: S 2006020203:2006020203(0)
ack 1119515694 win 4128 <mss 536> 13: 22:30:13.935864 10.0.30.2.41596 > 64.100.0.10.23: . ack 2006020204 win 4128 14: 22:30:13.946804 10.0.30.2.41596 > 64.100.0.10.23: P 1119515694:1119515706(12)
ack 2006020204 win 4128 15: 22:30:13.952679 10.0.30.2.41596 > 64.100.0.10.23: . ack 2006020204 win 4128 16: 22:30:14.013686 64.100.0.10.23 > 10.0.30.2.41596: P 2006020204:2006020216(12)
ack 1119515706 win 4116 17: 22:30:14.035352 64.100.0.10.23 > 10.0.30.2.41596: P 2006020216:2006020256(40)
ack 1119515706 win 4116 18: 22:30:14.045758 64.100.0.10.23 > 10.0.30.2.41596: P 2006020256:2006020259(3)
ack 1119515706 win 4116 19: 22:30:14.046781 64.100.0.10.23 > 10.0.30.2.41596: P 2006020259:2006020262(3)
ack 1119515706 win 4116 20: 22:30:14.047788 64.100.0.10.23 > 10.0.30.2.41596: P 2006020262:2006020268(6)
ack 1119515706 win 4116 21: 22:30:14.052151 10.0.30.2.41596 > 64.100.0.10.23: P 1119515706:1119515709(3)
ack 2006020256 win 4076 22: 22:30:14.089183 10.0.30.2.41596 > 64.100.0.10.23: P 1119515709:1119515712(3)
ack 2006020256 win 4076
ASA1# show cap capout 72 packets captured 1: 22:30:06.784871 10.0.30.2 > 10.0.10.3: icmp: echo request 2: 22:30:06.847688 10.0.10.3 > 10.0.30.2: icmp: echo reply 3: 22:30:06.878769 10.0.30.2 > 10.0.10.3: icmp: echo request 4: 22:30:06.900557 10.0.10.3 > 10.0.30.2: icmp: echo reply 5: 22:30:06.972758 10.0.30.2 > 10.0.10.3: icmp: echo request 6: 22:30:06.999399 10.0.10.3 > 10.0.30.2: icmp: echo reply 7: 22:30:07.076808 10.0.30.2 > 10.0.10.3: icmp: echo request 8: 22:30:07.134422 10.0.10.3 > 10.0.30.2: icmp: echo reply 9: 22:30:07.156959 10.0.30.2 > 10.0.10.3: icmp: echo request 10: 22:30:07.177420 10.0.10.3 > 10.0.30.2: icmp: echo reply 11: 22:30:13.803104 10.0.30.2.41596 > 10.0.10.3.23: S 2599614130:2599614130(0)
win 4128 <mss 536> 12: 22:30:13.860947 10.0.10.3.23 > 10.0.30.2.41596: S 4158597009:4158597009(0)
ack 2599614131 win 4128 <mss 536> 13: 22:30:13.936017 10.0.30.2.41596 > 10.0.10.3.23: . ack 4158597010 win 4128 14: 22:30:13.946941 10.0.30.2.41596 > 10.0.10.3.23: P 2599614131:2599614143(12)
ack 4158597010 win 4128 15: 22:30:13.952801 10.0.30.2.41596 > 10.0.10.3.23: . ack 4158597010 win 4128 16: 22:30:14.013488 10.0.10.3.23 > 10.0.30.2.41596: P 4158597010:4158597022(12)
ack 2599614143 win 4116 17: 22:30:14.035108 10.0.10.3.23 > 10.0.30.2.41596: P 4158597022:4158597062(40)
ack 2599614143 win 4116 18: 22:30:14.045377 10.0.10.3.23 > 10.0.30.2.41596: P 4158597062:4158597065(3)
ack 2599614143 win 4116 19: 22:30:14.046384 10.0.10.3.23 > 10.0.30.2.41596: P 4158597065:4158597068(3)
ack 2599614143 win 4116 20: 22:30:14.047406 10.0.10.3.23 > 10.0.30.2.41596: P 4158597068:4158597074(6)
ack 2599614143 win 4116 21: 22:30:14.052395 10.0.30.2.41596 > 10.0.10.3.23: P 2599614143:2599614146(3)
ack 4158597062 win 4076 22: 22:30:14.089427 10.0.30.2.41596 > 10.0.10.3.23: P 2599614146:2599614149(3)
ack 4158597062 win 4076
例如,如果您将VCS Control和VCS Expressway都连接到内部ASA接口的后面,如下例所示:

这种实施需要将VCS控制IP地址转换为ASA的内部IP地址,以强制返回流量返回到ASA,从而避免NAT反射出现非对称路由问题。
注意:如果VCS控制的源IP地址在此NAT转换期间使用两次NAT配置而不是建议的NAT反射配置更改,则VCS Expressway将看到来自其自身公有IP地址的流量,则MRA设备的电话服务不会出现。根据下面建议部分的第3部分,这不是支持的部署。
也就是说,强烈建议将VCS Expressway实施为Expressway-E双网络接口实施,而不是采用NAT反射的单个网卡。
强烈建议在处理Expressway-E传入或传出网络流量的防火墙上禁用SIP和H.323检测。启用时,经常发现SIP/H.323检测会对Expressway内置防火墙/NAT穿越功能产生负面影响。
以下示例说明如何在ASA上禁用SIP和H.323检测。
policy-map global_policy class inspection_default no inspect h323 h225 no inspect h323 ras no inspect sip
VCS Expressway(而不是具有NAT反射配置的VCS Expressway)的建议实施是双网络接口/双NIC VCS Expressway实施,有关详细信息,请检查下一链接。
ASA NAT 配置以及有关 Expressway-E 双网络接口实现的建议.
| 版本 | 发布日期 | 备注 |
|---|---|---|
1.0 |
30-Oct-2017
|
初始版本 |
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