HP 6120XG HP ProCurve Series 6120 Blade Switches Access Security Guide - Page 355

Example of an ACL with an Access Control Entry ACE that Allows Only One Source IP Address

Page 355 highlights

IPv4 Access Control Lists (ACLs) Traffic Management and Improved Network Performance . This ACL (a standard ACL named "Fileserver") includes an ACE (Access Control Entry) that permits matches only with the packets received from IP address 10.28.252.117 (the SA). Packets from any other source do not match and are denied. ip access-list standard Fileserver Source IP Address (SA) permit 10.28.252.117 0.0.0.0 ACE exit Mask (All zeros mean that a match occurs only when an IP packet's source address is identical to the source address configured in the ACE. Inbound Packet "A" On Port 20 - Destination Address: 10.35.248.184 - Source Address: 10.28.252.117 The port permits packet "A" because its source IP address matches the source address in the ACE. Inbound Packet "B" On Port 20 - Destination Address: 10.35.248.184 - Source Address: 10.28.252.120 The port denies (drops) packet "B" because its source IP address does not match the source address in the ACE. Figure 9-7. Example of an ACL with an Access Control Entry (ACE) that Allows Only One Source IP Address Examples Allowing Multiple IP Addresses. Table 9-4 provides examples of how to apply masks to meet various filtering requirements. Table 9-4. Example of Using an IP Address and Mask in an Access Control Entry IP Address in the ACE Mask Policy for a Match Between a Allowed IP Addresses Packet and the ACE A: 10.38.252.195 0.0.0.255 Exact match in first three octets only. 10.38.252.< 0-255 > (See row A in table 9-5, below.) B: 10.38.252.195 C: 10.38.252.195 D: 10.38.252.195 0.0.7.255 Exact match in the first two 10.38.< 248-255 >.< 0-255 > octets and the leftmost five bits (In the third octet, only the rightmost three bits are (248) of the third octet. wildcard bits. The leftmost five bits must be a match, and in the ACE, these bits are all set to 1. See row B in table 9-5, below.) 0.0.0.0 Exact match in all octets. 10.38.252.195 (There are no wildcard bits in any of the octets. See row C in table 9-5, below.) 0.15.255.255 Exact match in the first octet 10.< 32-47 >.< 0-255 >. and the leftmost four bits of the (In the second octet, the rightmost four bits are second octet. wildcard bits. See row D in table 9-5, below.) 9-31

  • 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

IPv4 Access Control Lists (ACLs)
Traffic Management and Improved Network Performance
.
Figure 9-7. Example of an ACL with an Access Control Entry (ACE) that Allows Only One Source IP Address
Examples Allowing Multiple IP Addresses.
Table 9-4 provides examples
of how to apply masks to meet various filtering requirements.
Table 9-4.
Example of Using an IP Address and Mask in an Access Control Entry
ip access-list standard Fileserver
permit 10.28.252.117 0.0.0.0
exit
Inbound Packet “A” On Port 20
– Destination Address: 10.35.248.184
– Source Address: 10.28.252.117
Inbound Packet “B” On Port 20
– Destination Address: 10.35.248.184
– Source Address: 10.28.252.120
This ACL (a standard ACL named “Fileserver”) includes an ACE (Access Control Entry)
that permits matches only with the packets received from IP address 10.28.252.117
(the SA). Packets from any other source do not match and are denied.
Source IP Address (SA)
Mask (All zeros mean that a match occurs
only when an IP packet’s source address is
identical to the source address configured
in the ACE.
The port permits packet “A” because
its source IP address matches the
source address in the ACE.
The port denies (drops) packet “B”
because its source IP address does
not match the source address in the
ACE.
ACE
IP Address in the ACE
Mask
Policy for a Match Between a
Packet and the ACE
Allowed IP Addresses
A:
10.38.252.195
0.0.0.255
Exact match in first three
octets only.
B:
10.38.252.195
0.0.7.255
Exact match in the first two
octets and the leftmost five bits
(248) of the third octet.
C:
10.38.252.195
0.0.0.0
Exact match in all octets.
D:
10.38.252.195
0.15.255.255
Exact match in the first octet
and the leftmost four bits of the
second octet.
10.38.252.< 0-255 >±
(See row A in table 9-5, below.)±
10.38.< 248-255 >.< 0-255 > ±
(In the third octet, only the rightmost three bits are ±
wildcard bits. The leftmost five bits must be a ±
match, and in the ACE, these bits are all set to 1. See ±
row B in table 9-5, below.)±
10.38.252.195
(There are no wildcard bits in any of the octets. See
row C in table 9-5, below.)
10.< 32-47 >.< 0-255 >.<0-255>±
(In the second octet, the rightmost four bits are ±
wildcard bits. See row D in table 9-5, below.) ±
9-31