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Dell S3100 Command Line Reference Guide for the Series 9.100.0 - Page 650

ip name-server

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Usage Information When you enter the no mtu command, Dell Networking OS reduces the ip mtu value to 1536 bytes. To return the IP MTU value to the default, use the no ip mtu command. Starting with Dell Networking OS Release 9.2(0.2), the ip mtu command is not supported to configure the IP MTU value that is used when the IP packet is fragmented. Instead of having to configure the IP MTU value, this value is automatically computed by the software when you configure an interface. As a result, the ip mtu command is not available for configuration. However, you can continue to specify the link MTU value by using the mtu command. Compensate for Layer 2 header when configuring link MTU on an Ethernet interface or Dell Networking OS may not fragment packets. If the packet includes a Layer 2 header, the difference between the link MTU and IP MTU (the ip mtu command) must be enough bytes to include for the Layer 2 header. Link MTU and IP MTU considerations for Port Channels and VLANs are as follows Port Channels: • All members must have the same link MTU value and the same IP MTU value. • The Port Channel link MTU and IP MTU must be less than or equal to the link MTU and IP MTU values configured on the channel members. For example, if the members have a link MTU of 2100 and an IP MTU 2000, the Port Channel's MTU values cannot be higher than 2100 for link MTU or 2000 bytes for IP MTU. VLANs: • All members of a VLAN must have same IP MTU value. • Members can have different Link MTU values. Tagged members must have a link MTU 4 bytes higher than untagged members to account for the packet tag. • The VLAN link MTU and IP MTU must be less than or equal to the link MTU and IP MTU values configured on the VLAN members. For example, the VLAN contains tagged members with Link MTU of 1522 and IP MTU of 1500 and untagged members with Link MTU of 1518 and IP MTU of 1500. The VLAN's Link MTU cannot be higher than 1518 bytes and its IP MTU cannot be higher than 1500 bytes. The following describes the difference between Link MTU and IP MTU. Layer 2 Overhead Difference between Link MTU and IP MTU Ethernet (untagged) VLAN Tag Untagged Packet with VLAN-Stack Header Tagged Packet with VLAN-Stack Header 18 bytes Tag 22 bytes 22 bytes 26 bytes Related Commands • mtu - set the link MTU for an Ethernet interface. ip name-server Enter up to six IPv4 addresses of name servers. The order you enter the addresses determines the order of their use. Syntax Parameters Defaults ip name-server ipv4-address [ipv4-address2...ipv4-address6] To remove a name server, use the no ip name-server ip-address command. ipv4-address ipv4-address2... ipv4-address6 Enter the IPv4 address, in dotted decimal format, of the name server to be used. (OPTIONAL) Enter up five more IPv4 addresses, in dotted decimal format, of name servers to be used. Separate the addresses with a space. No name servers are configured. 650 IPv4 Routing

Section	Page
Dell Command Line Reference Guide for the S3100 Series 9.10(0.0)	3
About this Guide	38
Objectives	38
Audience	38
Conventions	38
CLI Basics	39
Accessing the Command Line	39
Multiple Configuration Users	39
Obtaining Help	40
Navigating the CLI	41
Using the Keyword no Command	42
Filtering show Commands	42
Enabling Software Features on Devices Using a Command Option	42
feature vrf	43
show feature	43
Command Modes	44
File Management	52
boot system	52
cd	53
copy	54
delete	56
dir	57
format	58
fsck flash	59
mkdir	59
mount nfs	60
rmdir	60
upgrade system	61
rename	62
restore factory-defaults	63
show boot system	65
show bootvar	66
show file-systems	67
show os-version	68
show running-config	69
show startup-config	72
show version	73
upgrade	75
Control and Monitoring	77
banner exec	77
banner login	78
banner motd	79
cam-acl	80
cam-acl-vlan	81
clear line	82
configure	83
disable	83
do	84
enable	85
enable optic-info-update interval	86
end	87
exec-timeout	87
exit	88
ftp-server enable	89
ftp-server topdir	90
ftp-server username	91
hostname	92
ip http source-interface	92
ip http vrf	93
ip ftp password	94
ip ftp source-interface	95
ip ftp username	96
ip ftp vrf	96
ip telnet server enable	97
ip telnet server vrf	97
ip telnet source-interface	98
ip telnet vrf	99
ip tftp source-interface	100
ip tftp vrf	100
line	101
login concurrent-session	102
login statistics	103
motd-banner	105
ping	105
reload	108
send	109
service timestamps	109
show alarms	110
show cam-acl-vlan	111
show command-history	112
show cpu-traffic-stats	113
show debugging	114
show environment	115
show inventory	116
show login statistics	118
show memory	120
show processes cpu	121
show processes ipc flow-control	123
show processes memory	125
show software ifm	127
show system	128
show tech-support	131
ssh-peer-stack-unit	134
telnet	134
telnet-peer-stack-unit	136
terminal length	136
traceroute	137
undebug all	139
virtual-ip	139
write	140
802.1ag	142
ccm disable	142
ccm transmit-interval	143
clear ethernet cfm traceroute-cache	143
database hold-time	144
disable	144
domain	144
ethernet cfm	145
ethernet cfm mep	145
ethernet cfm mip	146
mep cross-check	146
mep cross-check enable	147
mep cross-check start-delay	147
ping ethernet	148
show ethernet cfm domain	148
show ethernet cfm maintenance-points local	149
show ethernet cfm maintenance-points remote	150
show ethernet cfm mipbd	151
show ethernet cfm statistics	151
show ethernet cfm port-statistics	152
show ethernet cfm traceroute-cache	153
service	153
traceroute cache hold-time	154
traceroute cache size	154
traceroute ethernet	155
802.1X	156
dot1x critical-vlan	157
debug dot1x	158
dot1x auth-fail-vlan	158
dot1x auth-server	159
dot1x auth-type mab-only	160
dot1x authentication (Configuration)	160
dot1x authentication (Interface)	161
dot1x guest-vlan	162
dot1x host-mode	163
dot1x mac-auth-bypass	163
dot1x max-eap-req	164
dot1x max-supplicants	165
dot1x port-control	165
dot1x profile	166
dot1x quiet-period	167
dot1x reauthentication	167
dot1x reauth-max	168
dot1x server-timeout	169
dot1x static-mab	170
dot1x supplicant-timeout	171
dot1x tx-period	171
mac	172
show dot1x cos-mapping interface	173
show dot1x interface	174
show dot1x profile	176
Access Control Lists (ACL)	177
Commands Common to all ACL Types	178
remark	178
show config	179
Common IP ACL Commands	180
access-class	180
clear counters ip access-group	181
ip access-group	182
ip control-plane egress-filter	183
show ip accounting access-list	183
show ip access-lists	185
Standard IP ACL Commands	185
deny	186
ip access-list standard	187
permit	188
resequence access-list	189
seq	190
Extended IP ACL Commands	191
deny	191
deny icmp	193
deny tcp	194
deny udp	197
ip access-list extended	199
permit	200
permit tcp	201
permit udp	203
resequence access-list	205
seq	206
Common MAC Access List Commands	208
clear counters mac access-group	208
mac access-group	209
show mac access-lists	210
show mac accounting access-list	211
Standard MAC ACL Commands	212
deny	212
mac access-list standard	213
permit	214
seq	215
Extended MAC ACL Commands	217
deny	217
mac access-list extended	218
permit	219
IP Prefix List Commands	221
clear ip prefix-list	221
deny	222
ip prefix-list	223
seq	223
show config	224
show ip prefix-list detail	225
show ip prefix-list summary	226
Route Map Commands	227
continue	227
description	228
match as-path	228
match community	229
match interface	230
match ip address	231
match ip next-hop	232
match ip route-source	233
match metric	233
match origin	234
match route-type	235
match tag	236
route-map	237
set as-path	238
set automatic-tag	238
set comm-list delete	239
set community	240
set level	241
set local-preference	242
set metric	243
set metric-type	244
set next-hop	244
set origin	245
set tag	246
set weight	247
show config	247
show route-map	248
AS-Path Commands	249
ip as-path access-list	249
show ip as-path-access-lists	250
IP Community List Commands	250
ip community-list	250
show ip community-lists	251
deny (for Standard IP ACLs)	252
deny (for Extended IP ACLs)	253
seq (for Standard IPv4 ACLs)	254
deny tcp (for Extended IP ACLs)	255
deny udp (for Extended IP ACLs)	256
deny arp (for Extended MAC ACLs)	257
deny icmp (for Extended IP ACLs)	258
deny ether-type (for Extended MAC ACLs)	259
deny (for Standard MAC ACLs)	260
deny (for Extended MAC ACLs)	262
permit (for Standard IP ACLs)	263
permit arp (for Extended MAC ACLs)	264
permit ether-type (for Extended MAC ACLs)	265
permit icmp (for Extended IP ACLs)	266
permit udp (for Extended IP ACLs)	267
permit (for Extended IP ACLs)	268
permit (for Standard MAC ACLs)	270
seq (for Standard MAC ACLs)	271
permit tcp (for Extended IP ACLs)	272
seq arp (for Extended MAC ACLs)	273
seq ether-type (for Extended MAC ACLs)	274
seq (for IP ACLs)	275
seq (for IPv6 ACLs)	276
permit udp (for IPv6 ACLs)	277
permit tcp (for IPv6 ACLs)	278
permit icmp (for IPv6 ACLs)	280
permit (for IPv6 ACLs)	281
deny udp (for IPv6 ACLs)	282
deny tcp (for IPv6 ACLs)	283
deny icmp (for Extended IPv6 ACLs)	284
deny (for IPv6 ACLs)	285
Access Control List (ACL) VLAN Groups and Content Addressable Memory (CAM)	287
member vlan	287
ip access-group	287
show acl-vlan-group	288
show cam-acl-vlan	289
cam-acl-vlan	290
show cam-usage	291
show running config acl-vlan-group	293
acl-vlan-group	293
show acl-vlan-group detail	294
description (ACL VLAN Group)	295
Bidirectional Forwarding Detection (BFD)	296
bfd all-neighbors	296
bfd disable	297
bfd enable (Configuration)	298
bfd enable (Interface)	298
bfd interval	299
bfd neighbor	300
bfd protocol-liveness	300
ip route bfd	301
ipv6 ospf bfd all-neighbors	302
isis bfd all-neighbors	303
neighbor bfd	304
neighbor bfd disable	304
show bfd neighbors	305
vrrp bfd neighbor	307
Border Gateway Protocol	308
BGP IPv4 Commands	308
address-family	308
aggregate-address	309
bgp add-path	310
bgp always-compare-med	311
bgp asnotation	312
bgp bestpath as-path ignore	313
bgp bestpath as-path multipath-relax	313
bgp bestpath med confed	314
bgp bestpath med missing-as-best	314
bgp bestpath router-id ignore	315
bgp client-to-client reflection	316
bgp cluster-id	316
bgp confederation identifier	317
bgp confederation peers	318
bgp connection-retry-timer	319
bgp dampening	319
bgp default local-preference	320
bgp dmzlink-bw	321
bgp enforce-first-as	322
bgp fast-external-fallover	322
bgp four-octet-as-support	323
bgp graceful-restart	324
bgp non-deterministic-med	325
bgp recursive-bgp-next-hop	325
bgp regex-eval-optz-disable	326
bgp router-id	327
clear ip bgp	328
clear ip bgp dampening	329
clear ip bgp flap-statistics	330
clear ip bgp peer-group	331
deny bandwidth	332
debug ip bgp	333
debug ip bgp dampening	334
debug ip bgp events	335
debug ip bgp keepalives	336
debug ip bgp notifications	336
debug ip bgp soft-reconfiguration	337
debug ip bgp updates	338
default-metric	339
description	340
maximum-paths	340
neighbor activate	341
neighbor add-path	342
neighbor advertisement-interval	343
neighbor advertisement-start	343
neighbor allowas-in	344
neighbor default-originate	345
neighbor description	346
neighbor distribute-list	346
neighbor ebgp-multihop	347
neighbor fall-over	348
neighbor local-as	349
neighbor maximum-prefix	350
neighbor password	351
neighbor peer-group (assigning peers)	352
neighbor peer-group (creating group)	353
neighbor peer-group passive	354
neighbor remote-as	354
neighbor remove-private-as	355
neighbor route-map	356
neighbor route-reflector-client	357
neighbor sender-side-loopdetect	358
neighbor send-community	359
neighbor shutdown	360
neighbor soft-reconfiguration inbound	360
neighbor timers	361
neighbor update-source	362
neighbor weight	363
network	364
network backdoor	365
permit bandwidth	366
redistribute	366
redistribute ospf	367
router bgp	368
set extcommunity bandwidth	369
show capture bgp-pdu neighbor	370
show config	371
show ip bgp	371
show ip bgp cluster-list	373
show ip bgp community	374
show ip bgp community-list	376
show ip bgp dampened-paths	378
show ip bgp detail	379
show ip bgp extcommunity-list	380
show ip bgp filter-list	381
show ip bgp flap-statistics	383
show ip bgp inconsistent-as	384
show ip bgp neighbors	386
show ip bgp next-hop	389
show ip bgp paths	390
show ip bgp paths community	391
show ip bgp peer-group	392
show ip bgp regexp	394
show ip bgp summary	395
show running-config bgp	397
timers bgp	398
MBGP Commands	399
debug ip bgp dampening	399
distance bgp	400
show ip bgp dampened-paths	401
BGP Extended Communities (RFC 4360)	402
set extcommunity rt	402
set extcommunity soo	403
show ip bgp paths extcommunity	404
show ip extcommunity-list	405
IPv6 BGP Commands	405
clear ip bgp ipv6 unicast soft	405
debug ip bgp ipv6 unicast soft-reconfiguration	406
ipv6 prefix-list	407
neighbor soft-reconfiguration inbound	407
show ipv6 prefix-list	408
IPv6 MBGP Commands	409
show ipv6 mbgproutes	409
Content Addressable Memory (CAM)	410
CAM Profile Commands	410
cam-acl (Configuration)	411
cam-acl-egress	413
cam-optimization	414
show cam-acl	414
test cam-usage	416
Control Plane Policing (CoPP)	418
control-plane-cpuqos	418
service-policy rate-limit-cpu-queues	418
service-policy rate-limit-protocols	419
ip unknown-unicast	420
ipv6 unknown-unicast	420
show cpu-queue rate cp	421
show ip protocol-queue-mapping	422
show ipv6 protocol-queue-mapping	422
show mac protocol-queue-mapping	423
Debugging and Diagnostics	425
Diagnostics and Monitoring Commands	425
logging coredump stack-unit	425
Offline Diagnostic Commands	426
diag stack-unit	426
offline stack-unit	427
online stack-unit	428
Hardware Commands	428
clear hardware stack-unit	428
clear hardware system-flow	429
clear hardware vlan-counters	430
hardware watchdog	430
show hardware mac	431
show hardware ip	431
show hardware stack-unit	432
show hardware buffer interface	440
show hardware counters interface	441
show hardware buffer-stats-snapshot	442
show hardware stack-unit buffer-stats-snapshot (Total Buffer Information)	443
show hardware system-flow	445
show hardware vlan-counters	447
show hardware drops	447
Dynamic Host Configuration Protocol (DHCP)	450
Commands to Configure the System to be a DHCP Server	450
clear ip dhcp	450
debug ip dhcp server	451
debug ipv6 dhcp	451
default-router	452
disable	452
dns-server	453
domain-name	453
excluded-address	454
hardware-address	455
host	455
lease	456
netbios-name-server	456
netbios-node-type	457
network	458
pool	458
show ip dhcp binding	459
show ip dhcp configuration	459
show ip dhcp conflict	460
show ip dhcp server	461
Commands to Configure Secure DHCP	461
arp inspection	461
arp inspection-trust	462
clear ip dhcp snooping	462
clear ipv6 dhcp snooping binding	464
ip dhcp relay	464
ip dhcp snooping	465
ipv6 dhcp snooping	465
ipv6 dhcp snooping vlan	466
ip dhcp snooping binding	466
IPv6 DHCP Snooping Binding	467
ip dhcp snooping database	468
ipv6 dhcp snooping database write-delay	468
ip dhcp snooping database renew	469
ipv6 dhcp snooping database renew	469
ip dhcp snooping trust	470
ipv6 dhcp snooping trust	470
ip dhcp source-address-validation	471
ip dhcp relay information-option	472
ip dhcp snooping verify mac-address	472
ipv6 dhcp snooping verify mac-address	473
ip helper-address	473
ipv6 helper-address	474
show ip dhcp snooping	474
show ipv6 dhcp snooping	477
Commands to Configure DNS	477
ip name-server	477
ip domain-name	478
ip domain-list	479
ip host	479
clear host	480
Equal Cost Multi-Path (ECMP)	481
ecmp-group	481

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Match case Limit results 1 per page

Usage Information

When you enter the

no mtu

command, Dell Networking OS reduces the ip mtu value to 1536 bytes. To return

the IP MTU value to the default, use the

no ip mtu

command.

Starting with Dell Networking OS Release 9.2(0.2), the

ip mtu

command is not supported to configure the IP

MTU value that is used when the IP packet is fragmented. Instead of having to configure the IP MTU value, this

value is automatically computed by the software when you configure an interface. As a result, the ip mtu

command is not available for configuration. However, you can continue to specify the link MTU value by using the

mtu command.

Compensate for Layer 2 header when configuring link MTU on an Ethernet interface or Dell Networking OS may

not fragment packets. If the packet includes a Layer 2 header, the difference between the link MTU and IP MTU

(the

ip mtu

command) must be enough bytes to include for the Layer 2 header.

Link MTU and IP MTU considerations for Port Channels and VLANs are as follows

Port Channels:

•

All members must have the same link MTU value and the same IP MTU value.

•

The Port Channel link MTU and IP MTU must be less than or equal to the link MTU and IP MTU values

configured on the channel members. For example, if the members have a link MTU of 2100 and an IP MTU

2000, the Port Channel’s MTU values cannot be higher than 2100 for link MTU or 2000 bytes for IP MTU.

VLANs:

•

All members of a VLAN must have same IP MTU value.

•

Members can have different Link MTU values. Tagged members must have a link MTU 4 bytes higher than

untagged members to account for the packet tag.

•

The VLAN link MTU and IP MTU must be less than or equal to the link MTU and IP MTU values configured on

the VLAN members. For example, the VLAN contains tagged members with Link MTU of 1522 and IP MTU of

1500 and untagged members with Link MTU of 1518 and IP MTU of 1500. The VLAN’s Link MTU cannot be

higher than 1518 bytes and its IP MTU cannot be higher than 1500 bytes.

The following describes the difference between Link MTU and IP MTU.

Layer 2

Overhead

Difference between Link MTU and IP MTU

Ethernet

(untagged)

18 bytes

VLAN Tag

Tag 22 bytes

Untagged Packet

with VLAN-Stack

Header

22 bytes

Tagged Packet

with VLAN-Stack

Header

26 bytes

Commands

•

mtu

— set the link MTU for an Ethernet interface.

ip name-server

Enter up to six IPv4 addresses of name servers. The order you enter the addresses determines the order of their use.

Syntax

ip name-server

ipv4-address

[

ipv4-address2...ipv4-address6

]

To remove a name server, use the

no ip name-server

ip-address

command.

Parameters

ipv4-address

Enter the IPv4 address, in dotted decimal format, of the name server to be used.

ipv4-address2...

ipv4-address6

(OPTIONAL) Enter up five more IPv4 addresses, in dotted decimal format, of name

servers to be used. Separate the addresses with a space.

Defaults

No name servers are configured.

650

IPv4 Routing