Catalyst C1300-24XT IP Helper Address Procedure

[iamroy]

I am trying to setup an IP HELPER-ADDRESS per SVI but clients are not getting IP address from the assigned DHCP Server in the IP HELPER Address.  C1300-24XT has also different syntax or argument in declaring IP HELPER-ADDRESS.

Catalyst 1300 Series Managed Switch, 24-port 10GE, 4x10G SFP+
System Object ID: 1.3.6.1.4.1.9.1.3250

Does any here could share the correct procedure for this? Thank you.

[Kasun Bandara]

@iamroy hi, can you share the configuration you did as of now?

[iamroy]

[iamroy]

Please disregard the previous config file. My apologies. Attached is the correct one.

[Kasun Bandara]

@iamroy hi, i see you have DHCP configured in switch. but helper address pointing to the IP range which is not inside the switch. can you explain the setup bit? such as are you using switch as a dhcp server or is there any separate dhcp server? is this helper address reachable to switch? do you have routes in place to reachability? 

[iamroy]

The CORE switch (10.0.1.254/24) has multiple VLANs (4, 6, 8, 16).
An external Windows DHCP server (10.0.1.250/24) is configured and reachable from the switch and all devices.
The  external Windows DHCP server, is successfully assigns IPs to VLANs on the same network of CORE switch ONLY but not on other VLANS.
Currently, the CORE C1300(10.0.254) device is handling DHCP for VLANs 6, 8, and 16.
All routing is in place, and there's full reachability between the switch, DHCP server, and clients.

[Kasun Bandara]

@iamroy hi, is this happening to the clients who connected to access switch terminated to port interface TenGigabitEthernet1/0/21? or all access switches?

[balaji.bandi]

ip helper-address all 10.0.1.250 37 42 49 53 137 138

you already have all VLAN helper address.

enable ip routing 

default-gateway means in normal cisco world just act as layer 2 switch, so try enable ip routing with ip route command to route and check, below CLI guide for reference.

https://www.cisco.com/c/en/us/td/docs/switches/campus-lan-switches-access/Catalyst-1200-and-1300-Switches/cli/C1300-cli/ip-routing-protocol-independent-commands.html?bookSearch=true#wp2483733251

still issue post below output :

show vlan

show ip interface brief

show ip route

show ip helper-address

[iamroy]

Routing is enabled and inter vlan connectivity is working.

DentalCore#show interfaces status
Flow Link Back Mdix
Port Type Duplex Speed Neg ctrl State Pressure Mode
-------- ------------ ------ ----- -------- ---- ----------- -------- -------
te1/0/1 10G-Copper Full 1000 Enabled Off Up Disabled Off
te1/0/2 10G-Copper Full 1000 Enabled Off Up Disabled On
te1/0/3 10G-Copper -- -- -- -- Down -- --
te1/0/4 10G-Copper -- -- -- -- Down -- --
te1/0/5 10G-Copper -- -- -- -- Down -- --
te1/0/6 10G-Copper -- -- -- -- Down -- --
te1/0/7 10G-Copper -- -- -- -- Down -- --
te1/0/8 10G-Copper -- -- -- -- Down -- --
te1/0/9 10G-Copper -- -- -- -- Down -- --
te1/0/10 10G-Copper -- -- -- -- Down -- --
te1/0/11 10G-Copper -- -- -- -- Down -- --
te1/0/12 10G-Copper -- -- -- -- Down -- --
te1/0/13 10G-Copper -- -- -- -- Down -- --
te1/0/14 10G-Copper -- -- -- -- Down -- --
te1/0/15 10G-Copper -- -- -- -- Down -- --
te1/0/16 10G-Copper -- -- -- -- Down -- --
te1/0/17 10G-Copper -- -- -- -- Down -- --
te1/0/18 10G-Copper -- -- -- -- Down -- --
te1/0/19 10G-Copper -- -- -- -- Down -- --
te1/0/20 10G-Copper -- -- -- -- Down -- --
te1/0/21 10G-Combo-C Full 1000 Enabled Off Up Disabled Off
te1/0/22 10G-Combo-C Full 1000 Enabled Off Up Disabled Off
te1/0/23 10G-Combo-C Full 1000 Enabled Off Up Disabled Off
te1/0/24 10G-Combo-C Full 1000 Enabled Off Up Disabled On

DentalCore#show vlan
Created by: D-Default, S-Static, G-GVRP, R-Radius Assigned VLAN, V-Voice VLAN

Vlan Name Tagged Ports UnTagged Ports Created by
---- ----------------- ------------------ ------------------ ----------------
1 1 te1/0/19-24 te1/0/11-18 D
4 mgt te1/0/13-18 te1/0/1-6, S
te1/0/19-24
6 server te1/0/13-24 S
8 faculty te1/0/13-24 te1/0/7-8 S
16 student te1/0/13-24 te1/0/9-10 S

DentalCore#show ip route
Maximum Parallel Paths: 1 (1 after reset)
IP Forwarding: enabled
Codes: > - best, C - connected, S - static,
R - RIP

S 0.0.0.0/0 [1/4] via 10.0.1.253, 151:10:22, vlan 4
C 10.0.1.0/24 is directly connected, vlan 4
C 10.0.8.0/21 is directly connected, vlan 8
C 10.0.16.0/20 is directly connected, vlan 16
C 192.168.6.0/24 is directly connected, vlan 6

DentalCore#show ip helper-address

Interface Helper Address Udp port
--------------- --------------- ------------------------
All 10.0.1.250 37,42,49,53,137,138

[balaji.bandi]

how is this switch connected to uplink - what port ?  where is DHCP Server located  ? does other network know return path for other IP address ?

post -

show ip interface brief

[iamroy]

C1300 is the CORE Switch.  The UPLINK ports of other Access Switches are connected to port21 to 24 of C1300 CORE Switch.

The Windows DHCP server is connected to port2 of the CORE Switch.

Command "show ip interface brief" is not applicable to this model, instead  the equivalent command is "show interface status"

====================
DentalCore#show ip interface brief
% Wrong number of parameters or invalid range, size or characters entered
DentalCore#
=====================

[balaji.bandi]

Looking at the configuration attached. port 21-24 (trunk and have native VLAN 4) and 21 configured access VLAN 4 (so that allow only VLAN 4) - so make sure you check the port 21 and test again.

for testing purpose - can you connect device to below ports on this switche and check is the DHCP offerning any IP :

interface TenGigabitEthernet1/0/6
switchport access vlan 4
!
interface TenGigabitEthernet1/0/7
switchport access vlan 8
!
interface TenGigabitEthernet1/0/9
switchport access vlan 16
!

Note : i  know some of the syntax not work on these model, just want to check is the SVI vlan 6, 8 and 16 are up ?

[iamroy]

Yes, same issue setting Access Ports with different VLANS on those mentioned ports of C1300.  Clients are getting IP from C1300 and not the Windows DHCP Server.   

Tried removing the DHCP pools in the C1300 Switch and clients in VLAN 6,8,16 are unable to get IP address.

Ports configured as Access Ports VLAN4 are getting IP from the Windows DHCP server.

[balaji.bandi]

Try disabling DHCP Server and test - if possible run debug and check DHCP relay working.

Since its working only for Native VLAN 4 not others.