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2650 Switch config w/ DHCP relay

ahking
Occasional Visitor

2650 Switch config w/ DHCP relay

I'm trying to migrate from a cisco switch to an HP 2650.

client connected to vlan 10 should get a 10.10.0/22 address

client connected to vlan 20 should get a 10.10.24/21 address

Watching my DHCP log I can see that all address request get tagged from the 10.10.16/22 which results in obvious error (below), since I don't have a scope for this range

dhcpd: DHCPDISCOVER from 00:1c:23:b5:8e:b1 via eth0: network 10.10.16/22: no free leases


DHCP server is 10.10.16.2

DHCP config below
*****************
ddns-update-style none;
ignore client-updates;
authoritative;
option domain-name "show.local";

subnet 10.10.0.0 netmask 255.255.252.0 {
option routers 10.10.0.1;
option subnet-mask 255.255.252.0;
option domain-name-servers 10.10.16.2,66.234.224.2,208.67.222.222;
option time-offset -48000;
option tftp-server-name "10.10.0.8";
default-lease-time 3600;
max-lease-time 7200;
range dynamic-bootp 10.10.0.10 10.10.3.254;
}

subnet 10.10.24.0 netmask 255.255.248.0 {
option routers 10.10.24.1;
option subnet-mask 255.255.248.0;
option domain-name-servers 10.10.16.2,66.234.224.2,208.67.222.222;
option time-offset -48000;
default-lease-time 3600;
max-lease-time 3600;
range dynamic-bootp 10.10.25.1 10.10.31.254;
}
*****************

switch config below
hostname "ProCurve Switch 2650"
ip routing
no ip directed-broadcast
snmp-server community "public" Unrestricted
vlan 1
name "DEFAULT_VLAN"
untagged 1-50
ip address 10.10.16.1 255.255.252.0
exit
vlan 10
name "shownet"
ip address 10.10.0.1 255.255.252.0
ip helper-address 10.10.16.2
tagged 41,47
exit
vlan 20
name "wireless"
ip address 10.10.24.1 255.255.248.0
ip helper-address 10.10.16.2
tagged 1-5,47
exit
ip route 0.0.0.0 0.0.0.0 10.10.16.2
password manager
password operator
***************

So what am I missing? Is it my routes?

Thanks
-Andrew
4 REPLIES
Evert Goor
Trusted Contributor

Re: 2650 Switch config w/ DHCP relay

The dhcp server answer no leases so no ip's
and i see in the configuration all ports in vlan1 who are on that 10.10.16.1 network.

The other vlans are only accessble in tagged mode.
Connect a pc to a port that is untagged in on of the vlans.

Good luck
ahking
Occasional Visitor

Re: 2650 Switch config w/ DHCP relay

I tried the following config but I don't get a DHCP address.

hostname "ProCurve Switch 2650"
ip routing
no ip directed-broadcast
snmp-server community "public" Unrestricted
vlan 1
name "DEFAULT_VLAN"
untagged 6-40,46-50
ip address 10.10.16.1 255.255.252.0
no untagged 1-5,41-45
exit
vlan 10
name "shownet"
untagged 1-5
ip address 10.10.0.1 255.255.252.0
ip helper-address 10.10.16.2
tagged 48
exit
vlan 20
name "wireless"
untagged 41-45
ip address 10.10.24.1 255.255.248.0
ip helper-address 10.10.16.2
tagged 48
exit
ip route 0.0.0.0 0.0.0.0 10.10.16.2
password manager
password operator


FYI - port 48 connects to my DHCP server (which is also my NAT/router box)
cenk sasmaztin
Honored Contributor

Re: 2650 Switch config w/ DHCP relay

hi Andrew

please check

must be your dhcp server ethernet card ip address
ip address 10.10.16.2
subnet musk 255.255.252.0
dafault gateway 10.10.16.1

and remove no ip directed-broadcast

you can write
(config)#ip directed-broadcast
cenk

cenk sasmaztin
Honored Contributor

Re: 2650 Switch config w/ DHCP relay

hi Andrew

client flood dhcp discover message on network with broadcast packet and dhcp server response to client dhcp offer packet with unicast packet

no ip directed-broadcast command break your dhcp server dhcp offer packet

there fore you make write this command

(config)#ip directed-broadcast


cenk

----------------------------------------
ProCurve(config)# ip directed-broadcast
Syntax: [no] ip directed-broadcast
ProCurve software makes the forwarding decision based on the routing switch's knowledge of the destination network prefix. Routers cannot determine
that a message is unicast or directed broadcast apart from the destination
network prefix. The decision to forward or not forward the message is by definition only possible in the last hop router.
To disable the directed broadcasts, enter the following CLI command:
ProCurve(config)# no ip directed-broadcast
cenk