Troublesome DHCP !

[cre8toruk]

Hi All,

I need some help! I'm trying to figure out why I can't get an IP address assigned via our existing DHCP server.

I have some new Cisco switches which will replace some old Dell switches but in the mean time I'm having to sort of merge the two infrastructures together while we migrate everything over.

The image should show the existing infrastructure.

The stuff in green is the existing infrastructure, the stuff in red is the new stuff.

The stuff in green works (obvs) but the stuff in red doesn't. I can ping the dhcp server from the Cisco layer 3 switch. If I manually set the ip address to 192.168.200.30 on the client I'm not able to ping the .200 gateway (200.254).  I'm obviously doing something wrong... HELP ! :-)

[cre8toruk]

Update: Ok I've added VLAN 200 to the trunk (Doh!) and now I can get a DHCP address....

[balaji.bandi]

You can set up IP DHCP helper-address on L3 interface is good enough to get IP address, since you mentioned you have reachability.

what device is this, can you post the config here.

[paul driver]

Hello

What switch is acting is performing the L3 inter vlan routing , I would assume looking at your topology it would be the dell 6224.but you say it the cisco 350, if so why do you have ip -default-gateway applied instead of a default or static route?
Can you post the config of the dell 6224- cisco 350 please.

[cre8toruk]

All sorted on this one now... it was simply a missing VLAN in the trunk I think.
I've remade both port channels and fingers crossed it seems to be working now.

Moving on (since I now have a working DHCP client :-))….

Previously my Pc has had to have two network cards in it, one one the client (200) VLAN and one on the Net management (254) VLAN.
As I'm implementing new switches I'd like to only have one network card but still be able to access the cli and consoles of all the new switches on the management VLAN (254).

I have assigned an IP address on VLAN 254 on each of the switches; 192.168.254.11, 12 & 13 respectively.

SW1 (VLAN254:192.168.254.11): is a layer 3 350XG with IP routing enabled and a default route of                 192.168.254.254 (the current dell layer 3 switch)
SW2 (VLAN254:192.168.254.12): is currently set as a layer 2 switch 

SW3 (VLAN254: 192.168.254.13): 

The Client PC is on VLAN 200 and has an ip address of 192.168.200.207

I can ping the Layer 3 core switch on 192.168.254.11, however I can't ping 192.168.254.12 or 192.168.254.13 (the switch I'm connected to), presumably because it doesn't know what to do with the return route i.e. 192.168.200.0... so cut a long story short(er), I enabled IP routing on SW3 (192.168.254.13) and gave it a default route as per SW1. This seems to have done the trick, however I still cant connect or ping SW2 on it's 192.168.254.12 ip.

So my questions are I guess is, is this the best way to do this? i.e. do ip routing or should there be a better way to do it?

Do we think I should enable Layer 3 capabilities on the layer 2 switch i.e. 192.168.254.12? Hopefully the diagram below makes some sense.

[paul driver]

Hello

---

@cre8toruk wrote:

Do we think I should enable Layer 3 capabilities on the layer 2 switch i.e. 192.168.254.12? Hopefully the diagram below makes some sense

---

No you shouldnt need to do that - however you didnt answer the last question  I asked which was what device is currently perfroming your intervlan routing as that would be where you would investigate any issue with inter-vlan connectivity to begin with.

[cre8toruk]

Hi, Sorry... I meant to reply to your post apologies... Currently the Dell 6224 is the ip gateway device, however the SG350XG is also set as a layer 3 switch and IP routing is enabled on it.
If I switch the 300 to a layer 3, It does seem to solve the problem though which would seem to bear out my theory. Ultimately the Dell switch will be retired and the new cisco kit will take over, it's complicated at the moment because I have to have both sets of infrastructure running and connected together.

[paul driver]

Hello

Can you share the config of the dell6224 and the cisco 300 please?

[cre8toruk]

300:

CORE-SW2
v1.4.11.2 / R800_NIK_1_4_216_022
CLI v1.0
set system mode router 

file SSD indicator encrypted
@
ssd-control-start 
ssd config 
ssd file passphrase control unrestricted 
no ssd file integrity control 
ssd-control-end cb0a3fdb1f3a1af4e4430033719968c0 
!
vlan database
vlan 10,17,101-103,190,200,254,400,2122,2126 
exit
ip dhcp relay address 192.168.10.10
ip dhcp relay address 192.168.10.11
ip dhcp relay enable
bonjour interface range vlan 1
hostname CORE-SW2
logging buffered warnings 
ip ssh server
clock timezone J 0 minutes 0
clock summer-time web recurring eu 
clock source browser
no ip domain lookup
!
interface vlan 1
 shutdown
!
interface vlan 10
 name SERVERS 
 ip address 192.168.10.102 255.255.255.0 
!
interface gigabitethernet24
 switchport mode access 
 switchport access vlan 254 
!
interface gigabitethernet51
 description CORE-SW-UPLINK-01
 channel-group 4 mode auto 
 no macro auto smartport 
 !next command is internal.
 macro auto smartport dynamic_type unknown 
!
interface gigabitethernet52
 description CORE-SW-UPLINK-02
 spanning-tree link-type point-to-point 
 channel-group 4 mode auto 
 macro description "switch "
 !next command is internal.
 macro auto smartport dynamic_type switch 
!
interface Port-channel1
 description SVR-HOST-01
 switchport trunk allowed vlan add 2122,2126 
 switchport trunk native vlan 10 
!
interface Port-channel2
 description SVR-HOST-02
 switchport trunk allowed vlan add 101-103,400 
 switchport trunk native vlan 10 
!
interface Port-channel3
 description EDGE-NETWORK
 spanning-tree link-type point-to-point 
 switchport trunk native vlan 200 
 macro description switch
 no macro auto smartport 
 !next command is internal.
 macro auto smartport dynamic_type switch 
!
interface Port-channel4
 description CORE-SW2
 spanning-tree link-type point-to-point 
 switchport trunk allowed vlan add 10,101-103,190,200,254,400,2122 
 switchport trunk allowed vlan add 2126 
 macro description "switch   "
 !next command is internal.
 macro auto smartport dynamic_type unknown 
!
exit
banner login 
################# CORE-SW2 ####################
########### No Unauthorised Access ############
###############################################


ip helper-address 192.168.200.0 192.168.10.10 37 42 49 53 137 138 
ip default-gateway 192.168.254.254 

DELL

!Current Configuration:
!System Description "PowerConnect 6224, 3.3.16.1, VxWorks 6.5"
!System Software Version 3.3.16.1
!Cut-through mode is configured as disabled
!
configure
vlan database
vlan 5,10,20-21,50-51,100-103,190,200,254,400,1000-1004,2000,2010,2122,2126
vlan routing 10 1
vlan routing 200 2
vlan routing 254 3
vlan routing 2000 4
vlan routing 5 5
vlan routing 2010 6
vlan routing 400 7
vlan routing 190 8
vlan routing 50 9
vlan routing 51 10
vlan association mac 0015.5D0A.0236 10
vlan association mac 0015.5D0A.0237 10
vlan association mac F01F.AF3D.5391 1

sntp unicast client enable
sntp server 192.168.10.10
sntp server 192.168.10.11 priority 2
clock summer-time recurring EU
stack
member 1 1
member 2 1

ip address 192.168.1.20 255.255.255.0
no ip domain-lookup
no ipv6 enable
no ipv6 forwarding
ip routing
ip route 0.0.0.0 0.0.0.0 192.168.254.1
ip helper-address 192.168.10.10 dhcp
ip helper-address 192.168.10.11 dhcp
ip helper-address 192.168.254.1 dhcp
ip helper-address 192.168.10.10 ntp
ip helper-address 192.168.10.11 ntp
router rip
no enable

interface vlan 10
name "Server VLAN"
routing
ip address 192.168.10.254 255.255.255.0
ipv6 mtu 1500
no ipv6 unreachables
no ip proxy-arp

interface vlan 200
name "Client VLAN"
routing
ip address 192.168.200.254 255.255.255.0
ipv6 mtu 1500
no ipv6 unreachables
no ip proxy-arp

interface vlan 254
name "Network VLAN"
routing
ip address 192.168.254.254 255.255.255.0
ipv6 mtu 1500
no ipv6 unreachables
no ip proxy-arp

interface vlan 2122
name "DSL Nimrod VLAN"

interface vlan 2126
name "DSL Cobham VLAN"

dhcp l2relay vlan 10
!

interface ethernet 1/g20
description "TEMP-CiscoXG"
switchport mode trunk
switchport trunk allowed vlan add 10,101-103,190,200,254
!

[paul driver]

Hello

First of all you have misconfiguration regards the dell and cisco l2 interconnects.

On the dell side it shows a single L2 interface with manual vlan pruning and on the cisco it shows two gig interfaces in portchannel again with manual vlan pruning but its differs from the dell, these should be the same on both sides?

So are you supposed to be aggregating the interfaces between the dell and cisco or is this supposed to be a single L2 interconnect?

[cre8toruk]

first off, I've no idea what manual pruning is. The L2 switch doesn't connect to the Dell it uses a port channel with 2 aggregated ports to connect to a L3 cisco (SW1). SW1 connects to the Dell on a single 10gbe port. I neglected to include that config I think in the list, apologies.
I've reset the 300 switch now and set it to switch mode... it all seems to be hanging together... so I think I'm good on this now.... That said see my other posts regarding some WIfi Ap's that I can't ping... so I'm not 100% there yet ! :-)