Home » D-Link Manuals » Wireless » D-Link DXS-5000-54S » Manual Viewer

D-Link DXS-5000-54S Emulator - Page 729

IP Helper Commands

View all D-Link DXS-5000-54S manuals

Add to My Manuals
Save this manual to your list of manuals

Page 729 highlights

5000 Series Layer 2/3 Managed Data Center Switch CLI Reference Guide IP Helper Commands This section describes the commands used to configure and monitor the IP Helper agent. IP Helper relays DHCP and other broadcast UDP packets from a local client to one or more servers which are not on the same network as the client. The IP Helper feature provides a mechanism that allows a router to forward certain configured UDP broadcast packets to a particular IP address. This allows various applications to reach servers on nonlocal subnets, even if the application was designed to assume a server is always on a local subnet and uses broadcast packets (with either the limited broadcast address 255.255.255.255, or a network directed broadcast address) to reach the server. Table 9: Default Ports - UDP Port Numbers Implied by Wildcard Protocol IEN-116 Name Service DNS NetBlOS Name Server NetBlOS Datagram Server TACACS+ Server Time Service DHCP Trivial File Transfer Protocol (TFTP) UDP Port Number 42 53 137 138 49 37 67 69 The system limits the number of relay entries to four times the maximum number of routing interfaces. The network administrator can allocate the relay entries as desired. There is no limit to the number of relay entries on an individual interface, and no limit to the number of servers for a given {interface, UDP port} pair. The relay agent relays DHCP packets in both directions. It relays broadcast packets from the client to one or more DHCP servers, and relays to the client packets that the DHCP server unicasts back to the relay agent. For other protocols, the relay agent only relays broadcast packets from the client to the server. Packets from the server back to the client are assumed to be unicast directly to the client. Because there is no relay in the return direction for protocols other than DHCP, the relay agent retains the source IP address from the original client packet. The relay agent uses a local IP address as the source IP address of relayed DHCP client packets. When a switch receives a broadcast UDP packet on a routing interface, the relay agent checks if the interface is configured to relay the destination UDP port. If so, the relay agent unicasts the packet to the configured server IP addresses. Otherwise, the relay agent checks if there is a global configuration for the destination UDP port. If so, the relay agent unicasts the packet to the configured server IP addresses. Otherwise the packet is not relayed. Note that if the packet matches a discard relay entry on the ingress interface, then the packet is not forwarded, regardless of the global configuration. The relay agent only relays packets that meet the following conditions: • The destination MAC address must be the all-ones broadcast address (FF:FF:FF:FF:FF:FF) • The destination IP address must be the limited broadcast address (255.255.255.255) or a directed broadcast address for the receive interface. • The IP time-to-live (TTL) must be greater than 1. • The protocol field in the IP header must be UDP (17). • The destination UDP port must match a configured relay entry. 7-112 clear ip helper statistics 723

Section	Page
Table of Contents	2
About This Guide	7
Objective and Audience	7
Acronyms and Abbreviations	7
Guide Conventions	11
1. About D-LINK OS Software	13
About D-LINK OS Software	13
Product Concept	13
2. Using the Command-Line	14
Command Syntax	14
Command Conventions	14
Common Parameter Values	15
Slot/Port Naming Convention	15
Using the No Form of a Command	16
Executing Show Commands	17
CLI Output Filtering	17
Example	17
3. D-LINK OS Modules	18
Command Modes	18
Command Completion and Abbreviation	21
CLI Error Messages	22
CLI Line-Editing Conventions	22
Using CLI Help	23
Accessing the CLI	24
4. Management Commands	25
Network Interface Commands	25
4-1 enable (Privileged EXEC access)	25
Parameters	25
Default	25
Command Mode	25
4-2 do (Privileged EXEC) commands	26
Parameters	26
Default	26
Command Mode	26
Example	26
4-3 serviceport ip	26
Parameters	27
Default	27
Command Mode	27
4-4 serviceport protocol	27
Parameters	27
Default	27
Command Mode	27
4-5 serviceport protocol dhcp	27
Parameters	27
Default	27
Command Mode	28
Usage Guideline	28
Example	28
4-6 network parms	28
Parameters	28
Default	28
Command Mode	28
4-7 network protocol	28
Parameters	29
Default	29
Command Mode	29
4-8 network protocol dhcp	29
Parameters	29
Default	29
Command Mode	29
Usage Guideline	29
Example	29
4-9 show network	29
Parameters	30
Default	30
Command Mode	30
Example	30
Display Parameters	30
4-10 show serviceport	31
Parameters	31
Default	31
Command Mode	31
Example	31
Display Parameters	31
IPv6 Management Commands	32
4-11 serviceport ipv6 enable	32
Parameters	32
Default	32
Command Mode	33
4-12 network ipv6 enable	33
Parameters	33
Default	33
Command Mode	33
4-13 serviceport ipv6 address	33
Parameters	33
Default	34
Command Mode	34
4-14 serviceport ipv6 gateway	34
Parameters	34
Default	34
Command Mode	34
4-15 serviceport ipv6 neighbor	34
Parameters	35
Default	35
Command Mode	35
4-16 network ipv6 neighbor	35
Parameters	35
Default	35
Command Mode	35
4-17 network ipv6 address	35
Parameters	36
Default	36
Command Mode	36
4-18 network ipv6 gateway	36
Parameters	36
Default	36
Command Mode	36
4-19 show network ipv6 neighbors	37
Parameters	37
Default	37
Command Mode	37
Example	37
Display Parameters	37
4-20 show serviceport ipv6 neighbors	37
Parameters	38
Default	38
Command Mode	38
Example	38
Display Parameters	38
4-21 show network ipv6 dhcp statistics	38
Parameters	39
Default	39
Command Mode	39
Example	39
Display Parameters	39
4-22 show serviceport ipv6 dhcp statistics	40
Parameters	40
Default	40
Command Mode	40
Example	40
Display Parameters	41
4-23 clear network ipv6 dhcp statistics	41
Parameters	41
Default	41
Command Mode	42
4-24 clear serviceport ipv6 dhcp statistics	42
Parameters	42
Default	42
Command Mode	42
4-25 ping ipv6	42
Parameters	42
Default	43
Command Mode	43
4-26 ping ipv6 interface	43
Parameters	43
Default	43
Command Mode	43
4-27 traceroute	44
Parameters	44
Default	45
Command Mode	45
Example	45
4-28 traceroute ipv6	47
Parameters	47
Default	47
Command Mode	47
Console Port Access Commands	47
4-29 configure	47
Parameters	47
Default	47
Command Mode	47
4-30 line	48
Parameters	48
Default	48
Command Mode	48
Example	48
4-31 session timeout	48
Parameters	48
Default	48
Command Mode	49
4-32 show serial	49
Parameters	49
Default	49
Command Mode	49
Example	49
Display Parameters	49
Telnet Commands	50
4-33 ip telnet server enable	50
Parameters	50
Default	50
Command Mode	50
4-34 ip telnet port	50
Parameters	50
Default	50
Command Mode	50
4-35 telnet	51
Parameters	51
Default	51
Command Mode	51
4-36 telnetcon maxsessions	51
Parameters	51
Default	51
Command Mode	52
4-37 telnetcon timeout	52
Parameters	52
Default	52
Command Mode	52
4-38 show telnet	52
Parameters	52
Default	52
Command Mode	52
Display Parameters	52
4-39 show telnetcon	53
Parameters	53
Default	53
Command Mode	53
Display Parameters	53
Secure Shell Commands	54
4-40 ip ssh server enable or ip ssh	54
Parameters	54
Default	54
Command Mode	54
4-41 ip ssh port	54
Parameters	54
Default	54
Command Mode	54
4-42 ip ssh protocol	55
Parameters	55
Default	55
Command Mode	55
4-43 ip ssh server enable	55
Parameters	55
Default	55
Command Mode	55
4-44 sshcon maxsessions	55
Parameters	56
Default	56
Command Mode	56
4-45 sshcon timeout	56
Parameters	56
Default	56
Command Mode	56
4-46 show ip ssh	56
Parameters	56
Default	57
Command Mode	57
Display Parameters	57
Management Security Commands	57
4-47 crypto key generate rsa	57
Parameters	57
Default	57
Command Mode	58
4-48 crypto key generate dsa	58
Parameters	58
Default	58
Command Mode	58
Access Commands	58
4-49 disconnect	58
Parameters	58
Default	58
Command Mode	59
4-50 linuxsh	59
Parameters	59
Default	59
Command Mode	59
4-51 show loginsession	59
Parameters	59
Default	59
Command Mode	59
Display Parameters	60
4-52 show loginsession long	60
Parameters	60
Default	60
Command Mode	60
Example	60
AAA Commands	60
4-53 aaa accounting	61
Parameters	61
Default	61
Command Mode	62
Example	62
4-54 aaa authentication commands	62
aaa authentication enable	62
Example	63
Parameters	63
Default	64
Command Mode	64
Example	64
aaa authentication login	64
Parameters	64
Default	65
Command Mode	65
Example	65
4-55 authorization commands	65
Parameters	65
Default	65
Command Mode	65
Example	65
4-56 aaa ias-user username	66
Parameters	66
Default	66
Command Mode	66
Example	66
4-57 aaa session-id	66
Parameters	67
Default	67
Command Mode	67
4-58 password (AAA IAS User configuration)	67
Parameters	67
Default	67
Command Mode	67
Example	67
4-59 clear aaa ias-users	68
Parameters	68
Default	68
Command Mode	68
Example	68
4-60 show aaa ias-users	68
Parameters	68
Default	69
Command Mode	69
Example	69
4-61 accounting	69
Parameters	69
Default	69
Command Mode	70
Example	70
4-62 show accounting	70
Parameters	70
Default	70
Command Mode	70
Example	70
4-63 show accounting methods	70
Parameters	71
Default	71
Command Mode	71
Example	71
4-64 show authorization methods	71
Parameters	71
Default	71
Command Mode	71
Example	71
4-65 login authentication	72
Parameters	72
Default	72
Command Mode	72
Example	73
User Account and Password Commands	73
4-66 username (Global Config)	73
Parameters	73
Default	73
Command Mode	74
Example	74
4-67 username name nopassword	74
Parameters	74
Default	75
Command Mode	75
4-68 username unlock	75
Parameters	75
Default	75
Command Mode	75
4-69 show users	75
Parameters	75
Default	75
Command Mode	76
Display Parameters	76
4-70 show users long	76
Parameters	76
Default	76
Command Mode	76
Example	76
4-71 show users accounts	76
Parameters	77
Default	77
Command Mode	77
Example	77
Display Parameters	77
4-72 show users login-history	78
Parameters	78
Default	78
Command Mode	78
Example	78
4-73 password (Line Configuration)	78
Parameters	78
Default	78
Command Mode	79
Example	79
4-74 password (User EXEC)	79
Parameters	79
Default	79
Command Mode	79
Example	79
4-75 enable password	80
Parameters	80
Default	80
Command Mode	80
Example	80
4-76 passwords min-length	80
Parameters	81
Default	81
Command Mode	81
4-77 passwords history	81
Parameters	81
Default	81
Command Mode	81
4-78 passwords aging	81
Parameters	81
Default	82
Command Mode	82
4-79 passwords lock-out	82
Parameters	82
Default	82
Command Mode	82
4-80 passwords strength-check	82
Parameters	82
Default	83
Command Mode	83
4-81 passwords strength maximum consecutive-characters	83
Parameters	83
Default	83
Command Mode	83
4-82 passwords strength maximum repeated-characters	83
Parameters	83
Default	83
Command Mode	83
4-83 passwords strength minimum uppercase-letters	84
Parameters	84
Default	84
Command Mode	84
4-84 passwords strength minimum lowercase-letters	84
Parameters	84
Default	84
Command Mode	84
4-85 passwords strength minimum numeric-characters	85
Parameters	85
Default	85
Command Mode	85
4-86 passwords strength minimum special-characters	85
Parameters	85
Default	85
Command Mode	85
4-87 passwords strength minimum character-classes	86
Parameters	86
Default	86
Command Mode	86
4-88 passwords strength exclude-keyword	86
Parameters	86
Default	86
Command Mode	86
4-89 show passwords configuration	87
Parameters	87
Default	87
Command Mode	87
Example	87
Display Parameters	87
4-90 show passwords result	88
Parameters	88
Default	88
Command Mode	88
Example	88
Display Parameters	89
SNMP Commands	89
4-91 snmp-server	89
Parameters	89
Default	90
Command Mode	90
4-92 snmp-server community	90
Parameters	90
Default	91
Command Mode	91
4-93 snmp-server community-group	91
Parameters	91
Default	91
Command Mode	91
4-94 snmp-server enable traps violation	91
Parameters	92
Default	92
Command Mode	92
4-95 snmp-server enable traps	92
Parameters	92
Default	92
Command Mode	92
Example	92
4-96 snmp-server enable traps bgp	93
Parameters	93
Default	93
Command Mode	93
4-97 snmp-server enable traps linkmode	93
Parameters	93
Default	93
Command Mode	93
4-98 snmp-server enable traps multiusers	93
Parameters	94
Default	94
Command Mode	94
4-99 snmp-server enable traps stpmode	94
Parameters	94
Default	94
Command Mode	94
4-100 snmp-server enginelD local	94
Parameters	95
Default	95
Command Mode	95
4-101 snmp-server filter	95
Parameters	95
Default	95
Command Mode	95
4-102 snmp-server group	96
Parameters	96

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1,000
1,001
1,002
1,003
1,004
1,005
1,006
1,007
1,008
1,009
1,010
1,011
1,012
1,013
1,014
1,015
1,016
1,017
1,018
1,019
1,020
1,021
1,022
1,023
1,024
1,025
1,026
1,027
1,028
1,029
1,030
1,031
1,032
1,033
1,034
1,035
1,036
1,037
1,038
1,039
1,040
1,041
1,042
1,043
1,044
1,045
1,046
1,047
1,048
1,049
1,050
1,051
1,052
1,053
1,054
1,055
1,056
1,057
1,058
1,059
1,060
1,061
1,062
1,063
1,064
1,065
1,066
1,067
1,068
1,069
1,070
1,071
1,072
1,073
1,074
1,075
1,076
1,077
1,078
1,079
1,080
1,081
1,082
1,083
1,084
1,085
1,086
1,087
1,088
1,089
1,090
1,091
1,092
1,093
1,094
1,095
1,096
1,097
1,098
1,099
1,100
1,101
1,102
1,103
1,104
1,105
1,106
1,107
1,108
1,109
1,110
1,111
1,112
1,113
1,114
1,115
1,116
1,117
1,118
1,119
1,120
1,121
1,122
1,123
1,124
1,125
1,126
1,127
1,128
1,129
1,130
1,131
1,132
1,133
1,134
1,135
1,136
1,137
1,138
1,139
1,140
1,141
1,142
1,143
1,144
1,145
1,146
1,147
1,148
1,149
1,150
1,151
1,152
1,153
1,154
1,155
1,156
1,157
1,158
1,159
1,160
1,161
1,162
1,163
1,164
1,165
1,166
1,167
1,168
1,169
1,170
1,171
1,172
1,173
1,174
1,175
1,176
1,177
1,178
1,179
1,180
1,181
1,182
1,183
1,184
1,185
1,186
1,187
1,188
1,189
1,190
1,191
1,192
1,193
1,194
1,195
1,196
1,197
1,198
1,199
1,200
1,201
1,202
1,203
1,204
1,205
1,206
1,207
1,208
1,209
1,210
1,211
1,212
1,213
1,214
1,215
1,216
1,217
1,218
1,219
1,220
1,221
1,222
1,223
1,224
1,225
1,226
1,227
1,228
1,229
1,230
1,231
1,232
1,233
1,234
1,235
1,236
1,237
1,238
1,239
1,240
1,241
1,242
1,243
1,244
1,245
1,246
1,247
1,248
1,249
1,250
1,251
1,252
1,253
1,254
1,255
1,256
1,257
1,258
1,259
1,260
1,261
1,262
1,263

Match case Limit results 1 per page

5000 Series Layer 2/3 Managed Data Center Switch CLI Reference Guide

723

IP Helper Commands

This section describes the commands used to configure and monitor the IP Helper agent. IP Helper

relays DHCP and other broadcast UDP packets from a local client to one or more servers which are not

on the same network as the client.

The IP Helper feature provides a mechanism that allows a router to forward certain configured UDP

broadcast packets to a particular IP address. This allows various applications to reach servers on non-

local subnets, even if the application was designed to assume a server is always on a local subnet and

uses broadcast packets (with either the limited broadcast address 255.255.255.255, or a network directed

broadcast address) to reach the server.

Table 9: Default Ports – UDP Port Numbers Implied by Wildcard

Protocol

UDP Port Number

IEN-116 Name Service

DNS

NetBlOS Name Server

137

NetBlOS Datagram Server

138

TACACS+ Server

Time Service

DHCP

Trivial File Transfer Protocol (TFTP)

The system limits the number of relay entries to four times the maximum number of routing interfaces.

The network administrator can allocate the relay entries as desired. There is no limit to the number of

relay entries on an individual interface, and no limit to the number of servers for a given {interface, UDP

port} pair.

The relay agent relays DHCP packets in both directions. It relays broadcast packets from the client to one

or more DHCP servers, and relays to the client packets that the DHCP server unicasts back to the relay

agent. For other protocols, the relay agent only relays broadcast packets from the client to the server.

Packets from the server back to the client are assumed to be unicast directly to the client. Because there

is no relay in the return direction for protocols other than DHCP, the relay agent retains the source IP

address from the original client packet. The relay agent uses a local IP address as the source IP address

of relayed DHCP client packets.

When a switch receives a broadcast UDP packet on a routing interface, the relay agent checks if the

interface is configured to relay the destination UDP port. If so, the relay agent unicasts the packet to the

configured server IP addresses. Otherwise, the relay agent checks if there is a global configuration for the

destination UDP port. If so, the relay agent unicasts the packet to the configured server IP addresses.

Otherwise the packet is not relayed. Note that if the packet matches a discard relay entry on the ingress

interface, then the packet is not forwarded, regardless of the global configuration.

The relay agent only relays packets that meet the following conditions:

•

The destination MAC address must be the all-ones broadcast address (FF:FF:FF:FF:FF:FF)

•

The destination IP address must be the limited broadcast address (255.255.255.255) or a

directed broadcast address for the receive interface.

•

The IP time-to-live (TTL) must be greater than 1.

•

The protocol field in the IP header must be UDP (17).

•

The destination UDP port must match a configured relay entry.

7-112 clear ip helper statistics