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Helpful
4
Replies

Unable to route traffic out

espitiav
Level 1
Level 1

‎09-24-2025 04:17 AM

i have a stack of 2 3750 layer 3 switches that house all my esxi hosts and SANs. its worked in the past with SDWAN but we have removed that and have a plain modem connected to the master switch on port gi1/0/24. Ive configured the port to layer 3 and have a static route pointed at the modems ip. The modem internet port is DHCP and ive tried configuring the uplink port to dhcp and it never ip binds. currently have it set to static ip to test but it doesnt work, i have no internet in any vlans. Help!!

 

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4 Replies 4

espitiav
Level 1
Level 1

‎09-24-2025 04:18 AM

Building configuration...

Current configuration : 14491 bytes
!
! Last configuration change at 21:34:36 EDT Tue Mar 29 2011
! NVRAM config last updated at 21:29:26 EDT Tue Mar 29 2011
!
version 15.0
no service pad
service timestamps debug datetime
service timestamps log datetime msec
service password-encryption
service sequence-numbers
service unsupported-transceiver
!
hostname CORE-SW
!
boot-start-marker
boot-end-marker
!
logging buffered 51200
!
no aaa new-model
clock timezone EST -5 0
clock summer-time EDT recurring
switch 1 provision ws-c3750x-24
switch 2 provision ws-c3750x-24
system mtu routing 1500
ip routing
!
ip dhcp pool hr
network 10.20.118.0 255.255.255.0
default-router 10.20.118.1
dns-server 8.8.8.8
lease 7
!
!
no ip domain-lookup
vtp mode transparent
!
!
spanning-tree mode rapid-pvst
spanning-tree extend system-id
!
!
!
!
!
!
!
!
!
vlan internal allocation policy ascending
!
vlan 10
name Corp-Wireless
!
vlan 11
name NFS-Storage
!
vlan 12
name vMotion
!
vlan 13
name FaultTolerance
!
vlan 14
name ServerMgmt
!
vlan 15
name Plant88
!
vlan 16
name Plant89
!
vlan 17
name Plant28
!
vlan 18
name HR
!
vlan 19
name NetworkMgmt
!
vlan 20
name ISP-Router
!
vlan 28
!
vlan 125
name Access-Points
!
vlan 150
!
vlan 999
name Guest-Wireless
!
ip ssh time-out 60
ip ssh authentication-retries 2
ip ssh version 2
lldp run
!
!
!
!
!
!
!
!
!
!
interface Port-channel1
description *PoC TR: PLANT28*
switchport trunk encapsulation dot1q
switchport mode trunk
!
interface Port-channel4
description EMC_SAN_LACP-SPA
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 11,14
switchport mode trunk
!
interface Port-channel5
description EMC_SAN_LACP-SPB
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 11,14
switchport mode trunk
!
interface FastEthernet0
no ip address
no ip route-cache
shutdown
!
interface GigabitEthernet1/0/1
description ESX TRUNKS
switchport trunk encapsulation dot1q
switchport trunk native vlan 14
switchport trunk allowed vlan 1,12-18
switchport mode trunk
spanning-tree bpduguard enable
!
interface GigabitEthernet1/0/2
description ESX TRUNKS
switchport trunk encapsulation dot1q
switchport trunk native vlan 14
switchport trunk allowed vlan 1,12-18
switchport mode trunk
spanning-tree bpduguard enable
!
interface GigabitEthernet1/0/3
description ESX TRUNKS
switchport trunk encapsulation dot1q
switchport trunk native vlan 14
switchport trunk allowed vlan 1,12-18
switchport mode trunk
spanning-tree bpduguard enable
!
interface GigabitEthernet1/0/4
description ESX TRUNKS
switchport trunk encapsulation dot1q
switchport trunk native vlan 14
switchport trunk allowed vlan 1,12-18
switchport mode trunk
spanning-tree bpduguard enable
!
interface GigabitEthernet1/0/5
description STORAGE PORTS
switchport access vlan 11
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet1/0/6
description STORAGE PORTS
switchport access vlan 11
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet1/0/7
description SAN LACP STORAGE PORTS
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 11,14
switchport mode trunk
channel-group 4 mode active
!
interface GigabitEthernet1/0/8
description STORAGE PORTS
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 11,14
switchport mode trunk
channel-group 5 mode active
!
interface GigabitEthernet1/0/9
switchport access vlan 28
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet1/0/10
switchport access vlan 14
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet1/0/11
switchport access vlan 14
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet1/0/12
switchport access vlan 14
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet1/0/13
description Voice VLAN
switchport access vlan 150
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 150
switchport mode trunk
switchport nonegotiate
switchport voice vlan 150
switchport priority extend trust
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet1/0/14
description Candor Kiosk
switchport mode access
switchport voice vlan 150
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet1/0/15
description access point
switchport access vlan 125
switchport mode access
spanning-tree portfast
!
interface GigabitEthernet1/0/16
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet1/0/17
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet1/0/18
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet1/0/19
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet1/0/20
description Trk to HP 1920
switchport trunk encapsulation dot1q
switchport mode trunk
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet1/0/21
switchport access vlan 20
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet1/0/22
description Arctic Wolf Mirror
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet1/0/23
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet1/0/24
description ****ISP LINK****
no switchport
ip address 74.125.227.5 255.255.248.0
spanning-tree bpduguard enable
!
interface GigabitEthernet1/1/1
description *TR: PLANT88*
switchport trunk encapsulation dot1q
switchport mode trunk
!
interface GigabitEthernet1/1/2
description *TR: PLANT88*
switchport trunk encapsulation dot1q
switchport mode trunk
!
interface GigabitEthernet1/1/3
description *PoC TR: PLANT28*
switchport trunk encapsulation dot1q
switchport mode trunk
channel-group 1 mode on
!
interface GigabitEthernet1/1/4
description ***ISP LINK***
switchport access vlan 20
switchport mode access
duplex full
spanning-tree portfast
spanning-tree bpduguard enable
!
interface TenGigabitEthernet1/1/1
!
interface TenGigabitEthernet1/1/2
!
interface GigabitEthernet2/0/1
description ESX TRUNKS
switchport trunk encapsulation dot1q
switchport trunk native vlan 14
switchport trunk allowed vlan 1,12-18
switchport mode trunk
spanning-tree bpduguard enable
!
interface GigabitEthernet2/0/2
description ESX TRUNKS
switchport trunk encapsulation dot1q
switchport trunk native vlan 14
switchport trunk allowed vlan 1,12-18
switchport mode trunk
spanning-tree bpduguard enable
!
interface GigabitEthernet2/0/3
description ESX TRUNKS
switchport trunk encapsulation dot1q
switchport trunk native vlan 14
switchport trunk allowed vlan 1,12-18
switchport mode trunk
spanning-tree bpduguard enable
!
interface GigabitEthernet2/0/4
description ESX TRUNKS
switchport trunk encapsulation dot1q
switchport trunk native vlan 14
switchport trunk allowed vlan 1,12-18
switchport mode trunk
spanning-tree bpduguard enable
!
interface GigabitEthernet2/0/5
description STORAGE PORTS
switchport access vlan 11
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet2/0/6
description STORAGE PORTS
switchport access vlan 11
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet2/0/7
description SAN LACP STORAGE PORTS
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 11,14
switchport mode trunk
channel-group 4 mode active
!
interface GigabitEthernet2/0/8
description STORAGE PORTS
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 11,14
switchport mode trunk
channel-group 5 mode active
!
interface GigabitEthernet2/0/9
switchport access vlan 14
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet2/0/10
switchport access vlan 14
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet2/0/11
switchport access vlan 14
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet2/0/12
switchport access vlan 14
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet2/0/13
switchport trunk encapsulation dot1q
switchport mode trunk
switchport voice vlan 150
switchport priority extend cos 5
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet2/0/14
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet2/0/15
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet2/0/16
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet2/0/17
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet2/0/18
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet2/0/19
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet2/0/20
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet2/0/21
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet2/0/22
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet2/0/23
switchport access vlan 18
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet2/0/24
switchport mode access
spanning-tree portfast
spanning-tree bpduguard enable
!
interface GigabitEthernet2/1/1
description *TR: PLANT88*
switchport trunk encapsulation dot1q
switchport mode trunk
!
interface GigabitEthernet2/1/2
!
interface GigabitEthernet2/1/3
!
interface GigabitEthernet2/1/4
description *PoC TR: PLANT28*
switchport trunk encapsulation dot1q
switchport mode trunk
channel-group 1 mode on
!
interface TenGigabitEthernet2/1/1
!
interface TenGigabitEthernet2/1/2
!
interface Vlan1
description OLD
ip address 10.20.110.1 255.255.255.0 secondary
ip address 10.20.100.1 255.255.255.0
ip helper-address 10.20.114.40
!
interface Vlan10
description Klaussner-Corp
ip address 10.20.111.1 255.255.255.0
ip helper-address 10.20.114.20
ip helper-address 10.20.114.40
!
interface Vlan14
description ServerMgmt
ip address 10.20.114.1 255.255.255.0
!
interface Vlan15
description Plant 88
ip address 10.20.115.1 255.255.255.0
!
interface Vlan16
description plant 89
ip address 10.20.116.1 255.255.255.0
!
interface Vlan17
description Plant 28
ip address 10.20.117.1 255.255.255.0
!
interface Vlan18
description HR
ip address 10.20.118.1 255.255.255.0
!
interface Vlan19
description NetworkManagement
ip address 10.20.119.1 255.255.255.0
!
interface Vlan20
description ISP-Router
no ip address
!
interface Vlan125
description Access-Points
ip address 10.20.125.1 255.255.255.0
ip helper-address 10.20.114.40
!
ip http server
ip http authentication local
ip http secure-server
!
ip route 0.0.0.0 0.0.0.0 GigabitEthernet1/0/24
ip route 0.0.0.0 0.0.0.0 74.125.227.1
!
!
!

line con 0
logging synchronous
line vty 0 4
login local
transport input telnet ssh
line vty 5 15
login local
transport input telnet ssh
!
!
monitor session 1 source interface Gi1/0/24
monitor session 1 destination interface Gi1/0/22
ntp server 192.5.41.40
ntp server 192.5.41.41
end

0 Helpful

Giuseppe Larosa
Hall of Fame
Hall of Fame

‎09-24-2025 05:20 AM

Hello @espitiav ,

there are some requirements to achieve internet connnectivity for internal subnets that are defined on your cat3750X L3 stack:

1) a working L3 link between the stack and the modem/router

2) the modem/router needs to have a WAN facing operational link. Contact the ISP to check what configuration is expected on the modem side. Check also if you have a green LED for the port if not there may be a cable problem.

3) the modem/router needs static routes for all internal subnets with next-hop = stack-IP-address on shared L3 link (point 1)

4) the modem/router needs to be configured for performing NAT for all internal subnets. This may be possible or not depending on the specific device you have. However, this a key point

if the modem/router cannot provide NAT for not connected internal private subnets you will need to add a router in the path between the modem and the L3 switch

Hope to help

Giuseppe

0 Helpful

espitiav
Level 1
Level 1
In response to Giuseppe Larosa

‎09-24-2025 06:23 AM

ahhhhhh i didint think of that. would adding a router between the modem and switch still require NAT on the modem side or on the router? i could possibly go that route if its the path of least resistance. i suppose my next step would be to contact the service provider and have them check their config.

0 Helpful

Giuseppe Larosa
Hall of Fame
Hall of Fame
In response to espitiav

‎09-24-2025 07:39 AM

Hello @espitiav ,

you should add a router on the path only if the modem is limited in NAT functionality. if the modem supports NAT for not directly subnets downstream via static routes you don't need the router.

Check if the modem uplink port has a solid GREEN Led on it . if it is there is some config issue.

Hope to help

Giuseppe

 

0 Helpful
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