Huawei V200R001C01 - Page 8

9.5 Congestion Avoidance Troubleshooting........................................................................................................257
9.5.1 Congestion Avoidance Fails to Take Effect..........................................................................................257
9.6 Congestion Management Troubleshooting.....................................................................................................260
9.6.1 Congestion Management Fails to Take Effect......................................................................................260
9.6.2 Troubleshooting Cases..........................................................................................................................263
10 Security......................................................................................................................................266
10.1 AAA Troubleshooting..................................................................................................................................267
10.1.1 RADIUS Authentication Fails.............................................................................................................267
10.1.2 HWTACACS Authentication Fails.....................................................................................................272
10.1.3 Troubleshooting Cases........................................................................................................................278
10.2 ARP Security Troubleshooting.....................................................................................................................284
10.2.1 The ARP Entry of an Authorized User Is Maliciously Modified........................................................284
10.2.2 The Gateway Address Is Maliciously Changed..................................................................................287
10.2.3 User Traffic Is Interrupted by a Large Number of Bogus ARP Packets.............................................289
10.2.4 IP Address Scanning Occurs...............................................................................................................291
10.2.5 ARP Learning Fails.............................................................................................................................294
10.3 NAC Troubleshooting..................................................................................................................................297
10.3.1 802.1x Authentication of a User Fails.................................................................................................297
10.3.2 MAC Address Authentication of a User Fails.....................................................................................301
10.3.3 MAC Address Bypass Authentication of a User Fails........................................................................305
10.4 Firewall Troubleshooting.............................................................................................................................305
10.4.1 SYN Flood Attacks Are Detected on a Network.................................................................................305
10.5 ACL Troubleshooting...................................................................................................................................307
10.5.1 Packet Filtering Firewall Fails Because of Invalid ACL Configuration.............................................307
10.6 NAT Troubleshooting...................................................................................................................................309
10.6.1 Internal Users Fail to Access the Public Network...............................................................................309
10.6.2 External Hosts Fail to Access Internal Servers...................................................................................312
10.6.3 Internal Host with a Conflicting IP Address Fails to Access an External Server................................315
11 Reliability..................................................................................................................................320
11.1 Interface Backup Troubleshooting...............................................................................................................321
11.1.1 Interface Backup Fails to Take Effect.................................................................................................321
11.1.2 Troubleshooting Cases........................................................................................................................324
11.2 BFD Troubleshooting...................................................................................................................................326
11.2.1 BFD Session Cannot Go Up................................................................................................................326
11.2.2 Interface Forwarding Is Interrupted After a BFD Session Detects a Fault and Goes Down...............329
11.2.3 Changed BFD Session Parameters Do Not Take Effect......................................................................331
11.2.4 Dynamic BFD Session Fails to Be Created.........................................................................................333
11.3 VRRP Troubleshooting................................................................................................................................335
11.3.1 Troubleshooting Cases........................................................................................................................335
12 VPN............................................................................................................................................340
12.1 GRE Troubleshooting...................................................................................................................................341
Huawei AR2200-S Series Enterprise Routers
Troubleshooting Contents
Issue 01 (2012-01-06) Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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