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Client can't reach Gateway and can't get IP from DHCP

So something strange happened, basically out of nowhere clients in a vlan can't reach their gateway and can't get a IP address from our DHCP. I looked into it and checked if all VLANs are configured and port configuration, I checked the output from "show spanning-tree vlan 110", it seems fine, my core is roout and all ports are forwarding, the vlan exists on all switches between core and access, so I am out of ideas. Any help?

30 Replies 30

balaji.bandi
Hall of Fame
Hall of Fame

where is your DHCP Server, do you have helper address on VLAN 110 SVI ?

can you post below information

show ip interface brief

show run interface vlan 110

show run interface x/x (where the device connected not getting IP)

 

what happends when you satically assign IP and able to ping gateway ?

 

by the way what device and IOS code running ?

BB

***** Rate All Helpful Responses *****

How to Ask The Cisco Community for Help

yes of course, my SVI has two ip helper addresses configured. 

Vlan110 10.226.0.1 YES NVRAM up up

 

interface Vlan110
description ## WLAN ##
ip address 10.226.0.1 255.255.252.0
ip helper-address 10.226.96.11
ip helper-address 10.226.96.100

and the device is an accesspoint but it does not matter what device I connect to that vlan.

interface GigabitEthernet1/0/5
description ## AP
switchport trunk native vlan 110
switchport mode trunk
storm-control broadcast level 0.80
storm-control multicast level 0.80
spanning-tree portfast edge
spanning-tree bpduguard enable

If I statically assign my IP address, I can't reach the gateway. So something is wrong with that vlan.

The original post described 2 symptoms "clients in a vlan can't reach their gateway and can't get a IP address from our DHCP." My initial reaction was that symptom 2 (can't get an IP from DHCP) explained the first symptom (can't reach gateway). But now you are saying that even with static IP you can not reach the gateway. So we have a different problem. From a device connected in that vlan can you post the output of ipconfig (or similar command depending on OS)? If you check the arp table of that device is there an arp entry for the gateway address?

HTH

Rick

So I connected my windows client to an access-port with vlan 110, my client gets an APIPA address and the arp -a command does not reveal any additional mac adresses.

Thanks for the additional information. It is helpful to know that a windows client does not receive an IP from DHCP and uses APIPA address. Does the configuratoin of vlan 100 have a helper address for the dhcp server? And does the dhcp server have a correct scope for that subnet?

When using an APIPA address I would not expect any entries in the arp table.

The post showing the mac flapping is interesting and should be investigated. But it shows that it affects vlans 125 and 225, but not 110. So I am not sure that this symptom is related to your original problem.

HTH

Rick

Well yes, it does have an IP-Helper and it is the right scope.

It seems there is a problem with a specific switch, I dont know exactly what. 

004449: Oct 11 09:23:35.723 CEST: %SW_MATM-4-MACFLAP_NOTIF: Host c0ee.fb4b.d7ef in vlan 225 is flapping between port Po1 and port Po13
004445: Oct 11 09:08:39.239 CEST: %SW_MATM-4-MACFLAP_NOTIF: Host 525a.e293.9af8 in vlan 225 is flapping between port Po1 and port Po25
004440: Oct 11 08:56:15.363 CEST: %SW_MATM-4-MACFLAP_NOTIF: Host 546c.eba4.ab0f in vlan 225 is flapping between port Po1 and port Po7
004433: Oct 11 08:46:16.707 CEST: %SW_MATM-4-MACFLAP_NOTIF: Host 804a.14a5.53cf in vlan 125 is flapping between port Po1 and port Po2

There is a lot of MAC-Flapping going on, on that switch.

easy dont worry 
do 
show vlan <<- do you see vlan and port assign to this vlan ?
show interface trunk <<- do you see vlan allow in trunk to CoreSW

No, I do not see any Ports assigned to any VLANs except VLAN 1. Also I see a lot of allowed VLANs to CoreSW.

Po1 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990

can I see show vlan and show interface trunk

gzplancist01-62#show vlan

VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Te1/0/19, Te1/0/21, Te1/1/2, Te1/1/7, Te2/0/14, Te2/0/18, Te2/0/21, Te2/1/2, Te2/1/5, Te2/1/6, Te2/1/7
2 Medical active
3 NC active
4 Werkstatt active
6 Hs58-Forensik active
10 MRT-Praxis active
12 Brainlab active
20 VSI active
66 BKHSCHWABEN active
85 Frimat-GLT-Forensik active
99 Management active
110 WLAN-MGMT active
115 LAN-MGMT active
120 bks-medical active
125 bks-intern active
130 WLAN-FAT-Clients active
140 PCs active
150 TCs active
160 Drucker active
170 Server-Hausnetz active
200 Zeiterfassung active
203 Zugangskontrolle active
204 IP_Kamera active
210 bks-mdm-install active
222 IAC-Gateway active
225 IACGast active
228 OP_Brainlab active
230 TK-Anlage active
231 TK-Clients active
233 TK-DECT active
244 GLT active
270 Media active
271 Schule active
272 PatTraining active
290 vlanSecunet active
295 POCT active
297 Medizintechnik active
300 bkspat.net active
500 RADIO-MR_Vida active
501 RADIO-Reserve active
502 RADIO-CT active
503 RADIO-XR active
504 RADIO-Roentgen_Ysio active
505 RADIO-CR_System active
506 RADIO-Ultraschall active
507 RADIO-Angio active
550 RADIO-Clients active
990 Laborumgebung active
1002 fddi-default act/unsup
1003 trcrf-default act/unsup
1004 fddinet-default act/unsup
1005 trbrf-default act/unsup

VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2
---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------
1 enet 100001 1500 - - - - - 0 0
2 enet 100002 1500 - - - - - 0 0
3 enet 100003 1500 - - - - - 0 0
4 enet 100004 1500 - - - - - 0 0
6 enet 100006 1500 - - - - - 0 0
10 enet 100010 1500 - - - - - 0 0
12 enet 100012 1500 - - - - - 0 0
20 enet 100020 1500 - - - - - 0 0
66 enet 100066 1500 - - - - - 0 0
85 enet 100085 1500 - - - - - 0 0
99 enet 100099 1500 - - - - - 0 0
110 enet 100110 1500 - - - - - 0 0
115 enet 100115 1500 - - - - - 0 0
120 enet 100120 1500 - - - - - 0 0
125 enet 100125 1500 - - - - - 0 0
130 enet 100130 1500 - - - - - 0 0
140 enet 100140 1500 - - - - - 0 0
150 enet 100150 1500 - - - - - 0 0
160 enet 100160 1500 - - - - - 0 0
170 enet 100170 1500 - - - - - 0 0
200 enet 100200 1500 - - - - - 0 0
203 enet 100203 1500 - - - - - 0 0
204 enet 100204 1500 - - - - - 0 0
210 enet 100210 1500 - - - - - 0 0
222 enet 100222 1500 - - - - - 0 0
225 enet 100225 1500 - - - - - 0 0
228 enet 100228 1500 - - - - - 0 0
230 enet 100230 1500 - - - - - 0 0
231 enet 100231 1500 - - - - - 0 0
233 enet 100233 1500 - - - - - 0 0
244 enet 100244 1500 - - - - - 0 0
270 enet 100270 1500 - - - - - 0 0
271 enet 100271 1500 - - - - - 0 0
272 enet 100272 1500 - - - - - 0 0
290 enet 100290 1500 - - - - - 0 0
295 enet 100295 1500 - - - - - 0 0
297 enet 100297 1500 - - - - - 0 0
300 enet 100300 1500 - - - - - 0 0
500 enet 100500 1500 - - - - - 0 0
501 enet 100501 1500 - - - - - 0 0
502 enet 100502 1500 - - - - - 0 0
503 enet 100503 1500 - - - - - 0 0
504 enet 100504 1500 - - - - - 0 0
505 enet 100505 1500 - - - - - 0 0
506 enet 100506 1500 - - - - - 0 0
507 enet 100507 1500 - - - - - 0 0
550 enet 100550 1500 - - - - - 0 0
990 enet 100990 1500 - - - - - 0 0
1002 fddi 101002 1500 - - - - - 0 0
1003 trcrf 101003 4472 1005 3276 - - srb 0 0
1004 fdnet 101004 1500 - - - ieee - 0 0
1005 trbrf 101005 4472 - - 15 ibm - 0 0


VLAN AREHops STEHops Backup CRF
---- ------- ------- ----------
1003 7 7 off

Remote SPAN VLANs
------------------------------------------------------------------------------


Primary Secondary Type Ports
------- --------- ----------------- ------------------------------------------

sh int trunk

Port Mode Encapsulation Status Native vlan
Te1/0/2 on 802.1q trunking 1
Te1/0/14 on 802.1q trunking 1
Te1/0/18 on 802.1q trunking 1
Te2/0/2 on 802.1q trunking 1
Te2/0/19 on 802.1q trunking 1
Po1 on 802.1q trunking 1
Po2 on 802.1q trunking 1
Po3 on 802.1q trunking 1
Po4 on 802.1q trunking 1
Po5 on 802.1q trunking 1
Po6 on 802.1q trunking 1
Po7 on 802.1q trunking 1
Po8 on 802.1q trunking 1
Po9 on 802.1q trunking 1
Po10 on 802.1q trunking 1
Po11 on 802.1q trunking 1
Po12 on 802.1q trunking 1
Po13 on 802.1q trunking 1
Po15 on 802.1q trunking 1
Po16 on 802.1q trunking 1
Po17 on 802.1q trunking 1
Po20 on 802.1q trunking 1
Po22 on 802.1q trunking 1
Po23 on 802.1q trunking 1
Po24 on 802.1q trunking 1
Po25 on 802.1q trunking 1
Po27 on 802.1q trunking 1
Po28 on 802.1q trunking 1
Po29 on 802.1q trunking 1
Po30 on 802.1q trunking 1

Port Vlans allowed on trunk
Te1/0/2 1-4094
Te1/0/14 1-4094
Te1/0/18 1-4094
Te2/0/2 1-4094
Te2/0/19 1-4094
Po1 1-4094
Po2 1-4094
Po3 1-4094
Po4 1-4094
Po5 1-4094
Po6 1-4094
Po7 1-4094
Po8 1-4094
Po9 1-4094
Po10 1-4094
Po11 1-4094
Po12 1-4094
Po13 1-4094
Po15 1-4094
Po16 1-4094
Po17 1-4094
Po20 1-4094

Port Vlans allowed on trunk
Po22 1-4094
Po23 1-4094
Po24 1-4094
Po25 1-4094
Po27 1-4094
Po28 1-4094
Po29 1-4094
Po30 1-4094

Port Vlans allowed and active in management domain
Te1/0/2 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Te1/0/14 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Te1/0/18 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Te2/0/2 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Te2/0/19 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po1 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po2 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po3 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po4 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po5 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po6 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po7 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po8 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po9 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po10 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po11 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po12 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po13 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po15 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po16 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po17 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po20 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po22 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po23 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po24 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po25 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po27 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po28 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po29 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po30 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990

Port Vlans in spanning tree forwarding state and not pruned
Te1/0/2 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Te1/0/14 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Te1/0/18 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Te2/0/2 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Te2/0/19 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po1 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po2 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po3 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po4 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po5 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po6 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po7 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po8 1,115,140,160,272
Po9 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990

Port Vlans in spanning tree forwarding state and not pruned
Po10 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po11 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po12 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po13 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po15 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po16 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po17 1-4,6,10,12,20,66,85,99,115,120,125,130,140,150,170,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500,502-503,505-507,550,990
Po20 1,110,115,140,160,200,204,231,270-271,290,295,297,500,502-503,990
Po22 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po23 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po24 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po25 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po27 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po28 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po29 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990
Po30 1-4,6,10,12,20,66,85,99,110,115,120,125,130,140,150,160,170,200,203-204,210,222,225,228,230-231,233,244,270-272,290,295,297,300,500-507,550,990

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