借助EPC和Packet-Trace排除IOS-XE SD-WAN问题的示例
简介
本文档介绍使用嵌入式数据包捕获(EPC)和数据包跟踪实用程序在运行Cisco IOS-XE SD-WAN的路由器上间歇性连接故障故障排除方法的示例。
问题
分支机构站点的用户报告说，如果用户空闲时间超过2-3分钟，使用直接互联网接入(DIA)的某些互联网应用（如SAP®、SSH、某些FTP客户端和其他应用集）将超时。如果它们在需要网络通信的应用程序内执行任何活动操作，则应用程序工作正常，不会发现任何问题。
例如，如果执行show version并使会话空闲超过2分钟，而没有任何活动，然后按键盘上的任意键，如以下输出所示：
router#Connection reset by 100.64.2.9 port 22
检查了路由器终端线路上的IDLE超时，发现exec-timeout设置为10分钟，不负责描述的行为（请记住，其他应用也受到影响）：
router#show user
Line User Host(s) Idle Location
* 1 vty 0 ekhabaro idle 00:00:00 10.149.4.41
Interface User Mode Idle Peer Address
unknown (ONEP) csrmgmt_infr 00:00:14
router#show line vty 0 | s Timeout
Timeouts: Idle EXEC Idle Session Modem Answer Session Dispatch
00:10:00 never none not set
Idle Session Disconnect Warning
never
Login-sequence User Response
00:00:30
Autoselect Initial Wait
not set
另一种实时体验问题的方法是连接到某些公共FTP。然后，如果尝试刷新目录列表、更改文件夹或在2-3分钟不活动后下载内容，则会看到消息（以红色显示）：
解决方案
此类问题有时难以排除，但是提供IOS-XE数据路径数据包跟踪功能和嵌入式数据包捕获(EPC)IOS-XE实用程序的极大帮助。这里是使用和故障排除方法的示例。
使用EPC排除故障
在路由器上配置并启动嵌入式数据包捕获(EPC)。由于此站点使用DIA，因此您需要分别捕获外部和内部接口上的流量。此处198.51.100.7是FTP服务器的IP地址，10.5.40.14是客户端的IP地址：
Branch#config-transaction admin connected from 127.0.0.1 using console on Branch Branch(config)# ip access-list extended CAP_ACL Branch(config-ext-nacl)# 10 permit ip any host 10.5.40.14 Branch(config-ext-nacl)# 20 permit ip host 10.5.40.14 any Branch(config-ext-nacl)# 30 permit ip any host 198.51.100.7 Branch(config-ext-nacl)# 40 permit ip host 198.51.100.7 any Branch(config-ext-nacl)# commit Commit complete. Branch(config-ext-nacl)# end Branch# Branch#monitor capture CAP_EXT interface GigabitEthernet 2 both Branch#monitor capture CAP_EXT interface GigabitEthernet 3 both Branch#monitor capture CAP_INT interface GigabitEthernet 7 both Branch#monitor capture CAP_EXT access-list CAP_ACL Branch#monitor capture CAP_INT access-list CAP_ACL Branch#monitor capture CAP_EXT start Started capture point : CAP_EXT Branch#monitor capture CAP_INT start Started capture point : CAP_INT
接下来，从用户的主机使用FileZilla FTP客户端连接到FTP服务器。确保在FTP客户端选项的Edit > Settings中禁用连接的FTP客户端超时：
默认情况下，FileZilla FTP客户端在20秒后关闭会话本身，您无法通过其他应用程序重现用户发现的问题。
约2-3分钟处于非活动状态后，尝试刷新目录列表：
然后，在FTP客户端中，您会看到屏幕截图中类似的错误消息：
接下来，检查是否在内部和外部接口上捕获了某些数据包，停止EPC和导出缓冲区：
Branch#show monitor capture CAP_EXT buffer buffer size (KB) : 10240 buffer used (KB) : 128 packets in buf : 37 packets dropped : 0 packets per sec : 24 Branch#show monitor capture CAP_INT buffer buffer size (KB) : 10240 buffer used (KB) : 128 packets in buf : 39 packets dropped : 0 packets per sec : 1 Branch#monitor capture CAP_INT stop_export Exported Successfully Branch#monitor capture CAP_EXT stop_export Exported Successfully
将捕获内容上传到您的PC，以便您能使用Wireshark分析它：
Branch#copy flash:CAP_INT.pcap sftp://admin:admin@203.0.113.36: vrf Mgmt-intf Address or name of remote host [203.0.113.36]? Destination username [admin]? Destination filename [CAP_INT.pcap]? SFTP send: Writing to /CAP_INT.pcap size 4362 ! 4362 bytes copied in 0.296 secs (14736 bytes/sec) Branch#copy flash:CAP_EXT.pcap sftp://admin:admin@203.0.113.36: vrf Mgmt-intf Address or name of remote host [203.0.113.36]? Destination username [admin]? Destination filename [CAP_EXT.pcap]? SFTP send: Writing to /CAP_EXT.pcap size 3839 ! 3839 bytes copied in 0.299 secs (12839 bytes/sec)
在单独的Wireshark窗口中打开两个文件，并设置Time Display Format，以便更轻松地通过时间戳将外部接口上的数据包与内部接口上的数据包关联起来：
然后调整窗口，注意在外部接口和内部接口上执行的数据包捕获之间的差异(在捕获中查找FTP PASV请求):
您可以看到该请求被发送到外部，并且发生了大量重新传输。此时，尚不清楚为什么来自外部主机的数据包（如88,90,92等数据包）未到达内部主机，但EPC为我们提供了宝贵信息，并确认某些数据包被cEdge路由器丢弃。
借助Cisco IOS-XE Packet Tracer实用程序排除故障
要进一步调查，必须使用数据包捕获和根据FTP服务器公有地址过滤数据：
debug platform condition ipv4 198.51.100.7/32 both debug platform packet-trace packet 1024 fia-trace data-size 4096 debug platform condition start !if you want to capture HEX data of the packet, use as well: debug platform packet-trace copy packet both size 2048 L2
然后，再次连接到FTP，等待2-3分钟以上，然后单击刷新按钮或再次下载内容。在日志中，您可以注意到相同的错误消息，如图所示：
现在，从packet-trace中，您可以看到其中一个数据包被丢弃：
134 Gi3 internal0/0/svc_eng:0 PUNT 64 (Service Engine packet) 135 Tu6000001 Gi7 FWD 136 Gi7 internal0/0/svc_eng:0 PUNT 64 (Service Engine packet) 137 Tu6000001 Gi3 FWD 138 Gi3 internal0/0/svc_eng:0 PUNT 64 (Service Engine packet) 139 Tu6000001 Gi7 FWD 140 Gi7 internal0/0/svc_eng:0 PUNT 64 (Service Engine packet) 141 Tu6000001 Gi3 FWD 142 Gi3 Gi3 DROP 479 (SdwanImplicitAclDrop) 143 Gi3 Gi3 DROP 479 (SdwanImplicitAclDrop) 144 Gi3 Gi3 DROP 479 (SdwanImplicitAclDrop) 145 Gi3 Gi3 DROP 479 (SdwanImplicitAclDrop) 146 Gi3 Gi3 DROP 479 (SdwanImplicitAclDrop) 147 Gi3 Gi3 DROP 479 (SdwanImplicitAclDrop) 148 Gi3 Gi3 DROP 479 (SdwanImplicitAclDrop) 149 Gi3 Gi3 DROP 479 (SdwanImplicitAclDrop) 150 Gi3 Gi3 DROP 479 (SdwanImplicitAclDrop) 151 Gi3 Gi3 DROP 479 (SdwanImplicitAclDrop)
您还可以检查特定数据包的详细信息：
Branch#show platform packet-trace packet 151
Packet: 151 CBUG ID: 151
Summary
Input : GigabitEthernet3
Output : GigabitEthernet3
State : DROP 479 (SdwanImplicitAclDrop) <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Timestamp
Start : 179731083510 ns (11/07/2019 13:08:27.567722 UTC)
Stop : 179731145820 ns (11/07/2019 13:08:27.567785 UTC)
Path Trace
Feature: IPV4(Input)
Input : GigabitEthernet3
Output : <unknown>
Source : 198.51.100.7
Destination : 100.64.2.10
Protocol : 6 (TCP)
SrcPort : 21
DstPort : 5801
Feature: DEBUG_COND_INPUT_PKT
Entry : Input - 0x817e8838
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 8280 ns
Feature: IPV4_INPUT_DST_LOOKUP_CONSUME
Entry : Input - 0x817e885c
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 4160 ns
Feature: SDWAN Implicit ACL <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Action : DISALLOW
Reason : SDWAN_SERV_TCP
Defer Action to Ingress ACL : No
Feature: STILE_LEGACY_DROP_EXT
Entry : Input - 0x81835c68
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 12900 ns
Feature: INGRESS_MMA_LOOKUP_DROP_EXT
Entry : Input - 0x8182be6c
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 14940 ns
Feature: INPUT_DROP_FNF_AOR_EXT
Entry : Input - 0x81819480
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 22040 ns
Feature: INPUT_FNF_DROP_EXT
Entry : Input - 0x818185bc
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 17580 ns
Feature: INPUT_DROP_FNF_AOR_RELEASE_EXT
Entry : Input - 0x81818e08
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 4680 ns
Feature: INPUT_DROP_EXT
Entry : Input - 0x817ed780
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 5540 ns
Feature: IPV4_SDWAN_IMPLICIT_ACL <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Entry : Input - 0x8183c774
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 449760 ns
Packet Copy In
00505608 6e500050 56add375 08004500 00363481 40002d06 122c5a82 46496440
020a0015 16a9f873 89d3efaa e3785019 00e523cb 00003432 31205469 6d656f75
Packet Copy Out
00505608 6e500050 56add375 08004500 00363481 40002c06 132c5a82 46496440
020a0015 16a9f873 89d3efaa e3785019 00e523cb 00003432 31205469 6d656f75
这些数据包从目标FTP服务器重新传输。在数据包捕获中，您已经看到类似的一组重传。
根据packet-trace输出，SD-WAN隐式ACL（实际上是隧道接口配置下允许的服务列表）似乎出于某种原因正在丢弃数据包。您可以从突出显示<<<<<标记的行中得出结论。要进行测试，请排除SD-WAN隐式ACL并允许配置相应外部接口中的所有服务：
Branch#config-transaction admin connected from 127.0.0.1 using console on Branch Branch(config)# sdwan Branch(config-sdwan)# interface GigabitEthernet3 Branch(config-interface-GigabitEthernet3)# tunnel-interface Branch(config-tunnel-interface)# allow-service all Branch(config-tunnel-interface)# commit Commit complete.
提交配置后，我们重复测试，但请确保停止数据包跟踪并在之前重新开始：
debug platform condition stop debug platform packet-trace packet 1024 fia-trace data-size 4096 debug platform condition start
当问题再次重现（例如，当您尝试更改目录时），并且连接根据FTP客户端的日志丢失（FTP客户端尝试重新连接）时，让我们再次看到packet-trace统计信息：
Branch# show platform packet-trace statistics
Packets Summary
Matched 292
Traced 292
Packets Received
Ingress 282
Inject 10
Count Code Cause
10 6 QFP Fwall generated packet
Packets Processed
Forward 134
Punt 134
Count Code Cause
5 22 QFP Fwall generated packet
129 64 Service Engine packet
Drop 24
Count Code Cause
21 55 ForUs
Consume 0
现在，您可以注意到另一个丢弃代码“DROP 55(ForUs)”，尽管您禁用了allow-service all配置的隐式ACL，但数据包仍在被丢弃。请仔细查看，并尝试了解丢弃的数据包和转发的数据包之间的差异：
Branch#show platform packet-trace summary <skipped> 269 Gi3 internal0/0/svc_eng:0 PUNT 64 (Service Engine packet) 270 Gi3 internal0/0/svc_eng:0 PUNT 64 (Service Engine packet) 271 Tu6000001 Gi7 FWD 272 Tu6000001 Gi7 FWD 273 Gi7 internal0/0/svc_eng:0 PUNT 64 (Service Engine packet) 274 Gi7 internal0/0/svc_eng:0 PUNT 64 (Service Engine packet) 275 Tu6000001 Gi3 FWD 276 Tu6000001 Gi3 FWD 277 Gi7 internal0/0/svc_eng:0 PUNT 64 (Service Engine packet) 278 Tu6000001 Gi3 FWD 279 Gi3 internal0/0/svc_eng:0 PUNT 64 (Service Engine packet) 280 Tu6000001 Gi7 FWD 281 Gi7 internal0/0/svc_eng:0 PUNT 64 (Service Engine packet) 282 Tu6000001 Gi3 FWD 283 Gi3 Gi3 DROP 55 (ForUs) 284 Gi3 Gi3 DROP 55 (ForUs) 285 Gi3 Gi3 DROP 55 (ForUs) 286 Gi3 Gi3 DROP 55 (ForUs) 287 Gi3 Gi3 DROP 55 (ForUs) 288 Gi3 Gi3 DROP 55 (ForUs) 289 Gi3 Gi3 DROP 55 (ForUs) 290 Gi3 Gi3 DROP 55 (ForUs) 291 Gi3 Gi3 DROP 55 (ForUs) 292 Gi3 Gi3 DROP 55 (ForUs) 293 Gi3 Gi3 DROP 55 (ForUs)
在上一输出中，Gi7是服务端接口，Gi3是传输端接口。例如，比较数据包279和数据包283之间的差异（重要差异用<<<<<）标记：
Branch#show platform packet-trace packet 279
Packet: 279 CBUG ID: 794
Summary
Input : GigabitEthernet3
Output : internal0/0/svc_eng:0
State : PUNT 64 (Service Engine packet)
Timestamp
Start : 142279273535701 ns (11/07/2019 12:46:47.57026 UTC)
Stop : 142279273732912 ns (11/07/2019 12:46:47.57223 UTC)
Path Trace
Feature: IPV4(Input)
Input : GigabitEthernet3
Output : <unknown>
Source : 198.51.100.7
Destination : 100.64.2.10
Protocol : 6 (TCP)
SrcPort : 28143
DstPort : 5668
Feature: DEBUG_COND_INPUT_PKT
Entry : Input - 0x817e8838
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 5880 ns
Feature: IPV4_INPUT_DST_LOOKUP_CONSUME
Entry : Input - 0x817e885c
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 7320 ns
Feature: SDWAN Implicit ACL <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Action : ALLOW
Reason : SDWAN_NAT_DIA <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Defer Action to Ingress ACL : No
Feature: IPV4_SDWAN_IMPLICIT_ACL
Entry : Input - 0x8183c774
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 112800 ns
Feature: IPV4_INPUT_FOR_US_MARTIAN
Entry : Input - 0x817e8860
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 78480 ns
Feature: DEBUG_COND_APPLICATION_IN
Entry : Input - 0x817e8848
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 1460 ns
Feature: DEBUG_COND_APPLICATION_IN_CLR_TXT
Entry : Input - 0x817e884c
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 120 ns
Feature: IPV4_INPUT_VFR <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Entry : Input - 0x817e89b0
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 3880 ns
Feature: NAT <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Direction : OUT to IN
Action : Translate Destination
Steps :
Match id : 1
Old Address : 100.64.2.10 05668
New Address : 10.5.40.14 49588
Feature: IPV4_NAT_INPUT_FIA <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Entry : Input - 0x8182c8a8
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 117600 ns
Feature: IPV4_INPUT_DST_LOOKUP_ISSUE_EXT
Entry : Input - 0x817e8858
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 19620 ns
Feature: RELOOKUP_NOTIFY_EXT
Entry : Input - 0x817eed90
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 14040 ns
Feature: IPV4_INTERNAL_DST_LOOKUP_CONSUME_EXT
Entry : Input - 0x817e8870
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 4620 ns
Feature: IPV4_INPUT_FOR_US_EXT
Entry : Input - 0x817e89a4
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 280 ns
Feature: IPV4_VFR_REFRAG_EXT
Entry : Input - 0x817e89c0
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 2720 ns
Feature: CFT
API : cft_handle_pkt
packet capabilities : 0x0000018c
input vrf_idx : 0
calling feature : STILE
direction : Input
triplet.vrf_idx : 3
triplet.network_start : 0x01003f8e
triplet.triplet_flags : 0x00000000
triplet.counter : 32
cft_bucket_number : 942419
cft_l3_payload_size : 20
cft_pkt_ind_flags : 0x00000100
cft_pkt_ind_valid : 0x00009bff
tuple.src_ip : 198.51.100.7
tuple.dst_ip : 10.5.40.14
tuple.src_port : 28143
tuple.dst_port : 49588
tuple.vrfid : 3
tuple.l4_protocol : TCP
tuple.l3_protocol : IPV4
pkt_sb_state : 0
pkt_sb.num_flows : 1
pkt_sb.tuple_epoch : 32
returned cft_error : 0
returned fid : 0xec4eeb70
Feature: NBAR
Packet number in flow: N/A
Classification state: Final
Classification name: ftp-data
Classification ID: [IANA-L4:20]
Classification source: Unknown
Number of matched sub-classifications: 0
Number of extracted fields: 0
Is PA (split) packet: False
TPH-MQC bitmask value: 0x0
Is optimized packet: False
Feature: IPV4_INPUT_STILE_LEGACY_EXT
Entry : Input - 0x81835ba8
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 315800 ns
Feature: IPV4_INPUT_FNF_FIRST_EXT
Entry : Input - 0x81818128
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 62200 ns
Feature: SDWAN_APP_ROUTE_POLICY_EXT
Entry : Input - 0x8183c758
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 12440 ns
Feature: SDWAN_DATA_POLICY_OUT_EXT
Entry : Input - 0x8183c754
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 12520 ns
Feature: IPV4_INPUT_LOOKUP_PROCESS_EXT
Entry : Input - 0x817e8864
Input : GigabitEthernet3
Output : GigabitEthernet7
Lapsed time : 8900 ns
Feature: IPV4_INPUT_IPOPTIONS_GOTO_OUTPUT_FEATURE_EXT
Entry : Output - 0x817e895c
Input : GigabitEthernet3
Output : GigabitEthernet7
Lapsed time : 9840 ns
Feature: CBUG_OUTPUT_FIA
Entry : Output - 0x817e8840
Input : GigabitEthernet3
Output : GigabitEthernet7
Lapsed time : 6520 ns
Feature: IPV4_OUTPUT_VFR
Entry : Output - 0x817e89b4
Input : GigabitEthernet3
Output : GigabitEthernet7
Lapsed time : 3660 ns
Feature: ZBFW
Action : Fwd
Zone-pair name : ZP_GUEST-INSIDE_OUTSID_642078363
Class-map name : BRANCH-DIA-GUEST-seq-11-cm_
Input interface : GigabitEthernet3
Egress interface : GigabitEthernet7
AVC Classification ID : 0
AVC Classification name: N/A
Feature: IPV4_OUTPUT_INSPECT
Entry : Output - 0x8181c97c
Input : GigabitEthernet3
Output : GigabitEthernet7
Lapsed time : 296980 ns
Feature: CFT
API : cft_handle_pkt
packet capabilities : 0x00000014
input vrf_idx : 0
calling feature : UTD
direction : Input
triplet.vrf_idx : 3
triplet.network_start : 0x01003f8e
triplet.triplet_flags : 0x00000004
triplet.counter : 32
cft_bucket_number : 942419
cft_l3_payload_size : 20
cft_pkt_ind_flags : 0x00000100
cft_pkt_ind_valid : 0x0000bbff
tuple.src_ip : 198.51.100.7
tuple.dst_ip : 10.5.40.14
tuple.src_port : 28143
tuple.dst_port : 49588
tuple.vrfid : 3
tuple.l4_protocol : TCP
tuple.l3_protocol : IPV4
pkt_sb_state : 0
pkt_sb.num_flows : 1
pkt_sb.tuple_epoch : 32
returned cft_error : 0
returned fid : 0xec4eeb70
Feature: UTD Policy (First FIA)
Action : Divert
Input interface : GigabitEthernet3
Egress interface: GigabitEthernet7
Feature: OUTPUT_UTD_FIRST_INSPECT
Entry : Output - 0x8183a0d8
Input : GigabitEthernet3
Output : GigabitEthernet7
Lapsed time : 117420 ns
Feature: UTD Inspection
Action : Divert
Input interface : GigabitEthernet3
Egress interface: GigabitEthernet7
Feature: OUTPUT_UTD_FINAL_INSPECT
Entry : Output - 0x8183a108
Input : GigabitEthernet3
Output : GigabitEthernet7
Lapsed time : 122900 ns
Feature: IPV4_OUTPUT_LOOKUP_PROCESS_EXT
Entry : Output - 0x817ee0e8
Input : GigabitEthernet3
Output : Tunnel6000001
Lapsed time : 10980 ns
Feature: IPV4_OUTPUT_GOTO_OUTPUT_FEATURE_EXT
Entry : Output - 0x817edfd0
Input : GigabitEthernet3
Output : Tunnel6000001
Lapsed time : 16200 ns
Feature: CBUG_OUTPUT_FIA
Entry : Output - 0x817e8840
Input : GigabitEthernet3
Output : Tunnel6000001
Lapsed time : 4960 ns
Feature: IPV4_OUTPUT_VFR
Entry : Output - 0x817e89b4
Input : GigabitEthernet3
Output : Tunnel6000001
Lapsed time : 520 ns
Feature: IPV4_OUTPUT_INSPECT
Entry : Output - 0x8181c97c
Input : GigabitEthernet3
Output : Tunnel6000001
Lapsed time : 4420 ns
Feature: IPV4_OUTPUT_THREAT_DEFENSE
Entry : Output - 0x81838278
Input : GigabitEthernet3
Output : Tunnel6000001
Lapsed time : 3300 ns
Feature: IPV4_VFR_REFRAG
Entry : Output - 0x817e89c0
Input : GigabitEthernet3
Output : Tunnel6000001
Lapsed time : 320 ns
Feature: DEBUG_COND_APPLICATION_OUT_CLR_TXT
Entry : Output - 0x817e8854
Input : GigabitEthernet3
Output : Tunnel6000001
Lapsed time : 4740 ns
Feature: UTD Encaps
Action : Encaps
Input interface : GigabitEthernet3
Egress interface: Tunnel6000001
Feature: IPV4_OUTPUT_L2_REWRITE
Entry : Output - 0x817e83b0
Input : GigabitEthernet3
Output : Tunnel6000001
Lapsed time : 296420 ns
Feature: DEBUG_COND_MAC_EGRESS
Entry : Output - 0x817e8844
Input : GigabitEthernet3
Output : Tunnel6000001
Lapsed time : 860 ns
Feature: DEBUG_COND_APPLICATION_OUT
Entry : Output - 0x817e8850
Input : GigabitEthernet3
Output : Tunnel6000001
Lapsed time : 300 ns
Feature: IPV4_OUTPUT_FRAG
Entry : Output - 0x817e89a8
Input : GigabitEthernet3
Output : Tunnel6000001
Lapsed time : 2560 ns
Feature: IPV4_OUTPUT_SDWAN_FNF_FINAL
Entry : Output - 0x818181b8
Input : GigabitEthernet3
Output : Tunnel6000001
Lapsed time : 100980 ns
Feature: IPV4_TUNNEL_OUTPUT_FINAL
Entry : Output - 0x81838bac
Input : Tunnel6000001
Output : Tunnel6000001
Lapsed time : 55460 ns
Feature: IPV4_TUNNEL_GOTO_OUTPUT
Entry : Output - 0x81838bb0
Input : Tunnel6000001
Output : Tunnel6000001
Lapsed time : 3920 ns
Feature: IPV4_TUNNEL_FW_CHECK_EXT
Entry : Output - 0x81838de8
Input : Tunnel6000001
Output : Tunnel6000001
Lapsed time : 9520 ns
Feature: IPV4_INPUT_DST_LOOKUP_ISSUE_EXT
Entry : Output - 0x817e8858
Input : Tunnel6000001
Output : Tunnel6000001
Lapsed time : 14960 ns
Feature: IPV4_INPUT_ARL_EXT
Entry : Output - 0x817e89d0
Input : Tunnel6000001
Output : Tunnel6000001
Lapsed time : 5680 ns
Feature: IPV4_INTERNAL_DST_LOOKUP_CONSUME_EXT
Entry : Output - 0x817e8870
Input : Tunnel6000001
Output : Tunnel6000001
Lapsed time : 1260 ns
Feature: IPV4_TUNNEL_ENCAP_FOR_US_EXT
Entry : Output - 0x81838db8
Input : Tunnel6000001
Output : Tunnel6000001
Lapsed time : 5460 ns
Feature: IPV4_INPUT_LOOKUP_PROCESS_EXT
Entry : Output - 0x817e8864
Input : Tunnel6000001
Output : VirtualPortGroup1
Lapsed time : 960 ns
Feature: IPV4_TUNNEL_ENCAP_GOTO_OUTPUT_FEATURE_EXT
Entry : Output - 0x817ee30c
Input : Tunnel6000001
Output : VirtualPortGroup1
Lapsed time : 13020 ns
Feature: CBUG_OUTPUT_FIA
Entry : Output - 0x817e8840
Input : Tunnel6000001
Output : VirtualPortGroup1
Lapsed time : 1980 ns
Feature: IPV4_OUTPUT_VFR
Entry : Output - 0x817e89b4
Input : Tunnel6000001
Output : VirtualPortGroup1
Lapsed time : 660 ns
Feature: IPV4_OUTPUT_INSPECT
Entry : Output - 0x8181c97c
Input : Tunnel6000001
Output : VirtualPortGroup1
Lapsed time : 15960 ns
Feature: IPV4_OUTPUT_THREAT_DEFENSE
Entry : Output - 0x81838278
Input : Tunnel6000001
Output : VirtualPortGroup1
Lapsed time : 1720 ns
Feature: IPV4_VFR_REFRAG
Entry : Output - 0x817e89c0
Input : Tunnel6000001
Output : VirtualPortGroup1
Lapsed time : 660 ns
Feature: DEBUG_COND_APPLICATION_OUT_CLR_TXT
Entry : Output - 0x817e8854
Input : Tunnel6000001
Output : VirtualPortGroup1
Lapsed time : 1560 ns
Feature: IPV4_OUTPUT_L2_REWRITE
Entry : Output - 0x817e83b0
Input : Tunnel6000001
Output : VirtualPortGroup1
Lapsed time : 10420 ns
Feature: DEBUG_COND_MAC_EGRESS
Entry : Output - 0x817e8844
Input : Tunnel6000001
Output : VirtualPortGroup1
Lapsed time : 520 ns
Feature: DEBUG_COND_APPLICATION_OUT
Entry : Output - 0x817e8850
Input : Tunnel6000001
Output : VirtualPortGroup1
Lapsed time : 180 ns
Feature: IPV4_OUTPUT_FRAG
Entry : Output - 0x817e89a8
Input : Tunnel6000001
Output : VirtualPortGroup1
Lapsed time : 940 ns
Feature: IPV4_OUTPUT_SDWAN_FNF_FINAL
Entry : Output - 0x818181b8
Input : Tunnel6000001
Output : VirtualPortGroup1
Lapsed time : 2560 ns
Feature: OUTPUT_SERVICE_ENGINE
Entry : Output - 0x81834550
Input : Tunnel6000001
Output : internal0/0/svc_eng:0
Lapsed time : 65820 ns
Feature: IPV4_INTERNAL_ARL_SANITY_EXT
Entry : Output - 0x817e89f4
Input : Tunnel6000001
Output : internal0/0/svc_eng:0
Lapsed time : 12280 ns
Feature: ZBFW
Action : Fwd
Zone-pair name : N/A
Class-map name : N/A
Input interface : Tunnel6000001
Egress interface : internal0/0/svc_eng:0
AVC Classification ID : 0
AVC Classification name: N/A
Feature: IPV4_OUTPUT_INSPECT_EXT
Entry : Output - 0x8181c97c
Input : Tunnel6000001
Output : internal0/0/svc_eng:0
Lapsed time : 38200 ns
Feature: IPV4_OUTPUT_THREAT_DEFENSE_EXT
Entry : Output - 0x81838278
Input : Tunnel6000001
Output : internal0/0/svc_eng:0
Lapsed time : 1980 ns
Feature: IPV4_VFR_REFRAG_EXT
Entry : Output - 0x817e89c0
Input : Tunnel6000001
Output : internal0/0/svc_eng:0
Lapsed time : 400 ns
Feature: IPV4_OUTPUT_DROP_POLICY_EXT
Entry : Output - 0x817e893c
Input : Tunnel6000001
Output : internal0/0/svc_eng:0
Lapsed time : 26240 ns
Feature: INTERNAL_TRANSMIT_PKT_EXT
Entry : Output - 0x817e88e4
Input : Tunnel6000001
Output : internal0/0/svc_eng:0
Lapsed time : 156540 ns
Branch#show platform packet-trace packet 283
Packet: 283 CBUG ID: 798
Summary
Input : GigabitEthernet3
Output : GigabitEthernet3
State : DROP 55 (ForUs)
Timestamp
Start : 142367023778233 ns (11/07/2019 12:48:14.807268 UTC)
Stop : 142367023853492 ns (11/07/2019 12:48:14.807343 UTC)
Path Trace
Feature: IPV4(Input)
Input : GigabitEthernet3
Output : <unknown>
Source : 198.51.100.7
Destination : 100.64.2.10
Protocol : 6 (TCP)
SrcPort : 21
DstPort : 5635
Feature: DEBUG_COND_INPUT_PKT
Entry : Input - 0x817e8838
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 12340 ns
Feature: IPV4_INPUT_DST_LOOKUP_CONSUME
Entry : Input - 0x817e885c
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 7140 ns
Feature: SDWAN Implicit ACL <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Action : ALLOW
Reason : SDWAN_SERV_ALL <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Defer Action to Ingress ACL : No
Feature: IPV4_SDWAN_IMPLICIT_ACL
Entry : Input - 0x8183c774
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 139700 ns
Feature: IPV4_INPUT_FOR_US_MARTIAN
Entry : Input - 0x817e8860
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 97840 ns
Feature: DEBUG_COND_APPLICATION_IN
Entry : Input - 0x817e8848
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 2260 ns
Feature: DEBUG_COND_APPLICATION_IN_CLR_TXT
Entry : Input - 0x817e884c
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 140 ns
Feature: IPV4_INPUT_VFR <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Entry : Input - 0x817e89b0
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 5860 ns
Feature: OCE_TRACE(Input) <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Input : GigabitEthernet3
Output : <unknown>
Type : OCE_ADJ_RECEIVE
Feature: IPV4_NAT_INPUT_FIA <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
Entry : Input - 0x8182c8a8
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 166780 ns
Feature: STILE_LEGACY_DROP_EXT
Entry : Input - 0x81835c68
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 1920 ns
Feature: INGRESS_MMA_LOOKUP_DROP_EXT
Entry : Input - 0x8182be6c
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 8340 ns
Feature: INPUT_DROP_FNF_AOR_EXT
Entry : Input - 0x81819480
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 10920 ns
Feature: INPUT_FNF_DROP_EXT
Entry : Input - 0x818185bc
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 6460 ns
Feature: INPUT_DROP_FNF_AOR_RELEASE_EXT
Entry : Input - 0x81818e08
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 2240 ns
Feature: INPUT_DROP_EXT
Entry : Input - 0x817ed780
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 1200 ns
Feature: IPV4_INPUT_LOOKUP_PROCESS
Entry : Input - 0x817e8864
Input : GigabitEthernet3
Output : <unknown>
Lapsed time : 176340 ns
如您所见，主要区别是，通常使用代码SDWAN_NAT_DIA和丢弃的数据包SDWAN_SERV_ALL来允许来自外部的数据包。此外，在IPV4_INPUT_VFR和IPV4_NAT_INPUT_FIA功能之间，对于允许的数据包，涉及不同的IOS-XE功能，即NAT和OCE_TRACE。所有差异都可能让您知道问题与NAT有关，因此，我们在建立FTP会话后检查NAT转换：
Branch#show ip nat translations tcp verbose | b 198.51.100.7 tcp 100.64.2.10:5801 10.5.40.14:49648 198.51.100.7:21 198.51.100.7:21 create: 11/07/19 13:02:05, use: 11/07/19 13:02:06, timeout: 00:00:57 Map-Id(In): 1 Flags: unknown Appl type: none WLAN-Flags: unknown Mac-Address: 0000.0000.0000 Input-IDB: VRF: 40, entry-id: 0xee541ec0, use_count:1 In_pkts: 24 In_bytes: 698, Out_pkts: 13 Out_bytes: 605 Output-IDB: GigabitEthernet3 tcp 100.64.2.10:5795 10.5.40.14:49644 52.179.129.229:443 52.179.129.229:443 create: 11/07/19 13:01:18, use: 11/07/19 13:01:18, timeout: 00:00:09 Map-Id(In): 1 Flags: timing-out Appl type: none WLAN-Flags: unknown Mac-Address: 0000.0000.0000 Input-IDB: VRF: 40, entry-id: 0xee542640, use_count:1 In_pkts: 29 In_bytes: 5114, Out_pkts: 12 Out_bytes: 7113 Output-IDB: GigabitEthernet3 tcp 100.64.2.10:5802 10.5.40.14:49649 198.51.100.7:21319 198.51.100.7:21319 create: 11/07/19 13:02:06, use: 11/07/19 13:02:06, timeout: 00:00:57 Map-Id(In): 1 Flags: timing-out Appl type: none WLAN-Flags: unknown Mac-Address: 0000.0000.0000 Input-IDB: VRF: 40, entry-id: 0xee541380, use_count:1 In_pkts: 8 In_bytes: 184, Out_pkts: 4 Out_bytes: 837 Output-IDB: GigabitEthernet3 tcp 100.64.2.10:5800 10.5.40.14:49636 198.51.100.7:21 198.51.100.7:21 create: 11/07/19 13:02:05, use: 11/07/19 13:02:05, timeout: 00:00:56 Map-Id(In): 1 Flags: timing-out Appl type: none WLAN-Flags: unknown Mac-Address: 0000.0000.0000 Input-IDB: VRF: 40, entry-id: 0xee5423c0, use_count:1 In_pkts: 2 In_bytes: 66, Out_pkts: 1 Out_bytes: 20 Output-IDB: GigabitEthernet3 tcp 100.64.2.10:5633 10.5.40.14:49432 52.242.211.89:443 52.242.211.89:443 create: 11/07/19 12:44:18, use: 11/07/19 13:01:17, timeout: 00:00:08 Map-Id(In): 1 Flags: unknown Appl type: none WLAN-Flags: unknown Mac-Address: 0000.0000.0000 Input-IDB: VRF: 40, entry-id: 0xee527840, use_count:1 In_pkts: 53 In_bytes: 6257, Out_pkts: 29 Out_bytes: 7030 Output-IDB: GigabitEthernet3 tcp 100.64.2.10:5792 10.5.40.14:49647 51.143.111.7:443 51.143.111.7:443 create: 11/07/19 13:02:00, use: 11/07/19 13:02:09, timeout: 00:01:00 Map-Id(In): 1 Flags: syn_in Appl type: none WLAN-Flags: unknown Mac-Address: 0000.0000.0000 Input-IDB: VRF: 40, entry-id: 0xee542500, use_count:1 In_pkts: 6 In_bytes: 224, Out_pkts: 3 Out_bytes: 96 Output-IDB: GigabitEthernet3 Total number of translations: 12
请注意超时。它看起来低得可疑吗？在FTP客户端处于非活动状态约2-3分钟后，再次检查，您会发现NAT表中没有转换：
Branch# show ip nat translations | i 198.51.100.7 Branch#
瞧！因此，问题的根本原因是：会话过快，尽管从FTP客户端会话的角度来看，cEdge路由器对该TCP会话一无所知，并丢弃返回的流量。如果检查配置，您会发现NAT会话超时配置为120秒，可能是错误的：
Branch#show run | i tcp-timeout ip nat translation tcp-timeout 120 Branch#
此计时器必须在vManage上的相应设备模板中固定：
例如，将其更改为60分钟，然后问题解决。
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