Wired Intelligent Edge

0Hi:

I configured HP 2530 with 2 VLANS (VALN 2 and VLAN3).

There is a linux server acting as a router with two network interfaces (one in VLAN 2 with IP 192.168.20.1 and the other in VLAN 3 with IP 192.168..30.1). There isn´t any filtered traffic, only ip fordwarding.

The network address are:

VLAN 2 (192.168.20.0/24)

VLAN 3 (192.168.30.0/24)

In this scenario, everything works fine. I placed some workstations in both VLANs/subnets and there isn´t any connectivity problem.

Now, I configured a DHCP server placed in VLAN2 (with IP 192.168.20.200). It has two scopes:

SCOPE 1: 192.168.20.2 – 192.168.20.5 with default gateway 192.168.20.1 (for worksrtations in VLAN 2)

SCOPE 2: 192.168.30.2 – 192.168.30.5 with default gateway 192.168.30.1 (for worksrtations in VLAN 3)

Only workstations in VLAN 2 get address from DHCP server.

This is the switch configuration:

ip default-gateway 192.168.20.1

vlan 1

name "DEFAULT_VLAN"

no untagged 1-30

untagged 31-52

no ip address

exit

vlan 2

name "VLAN2”

untagged 1-15

ip address 192.168.20.201 255.255.255.0

exit

vlan 3

name "VLAN3"

untagged 16-30

ip address 192.168.30.201 255.255.255.0

ip helper-address 192.168.20.200

exit

There isn´t any connectivity problem. For example, I can ping from a workstation in VLAN 3 (static IP address 192.168.30.30) to DHCP Server (192.168.20.200) and from DHCP server (192.168.20.200) to any workstation in VLAN 3 (192.168.30.30, for example). But DHCP isn´t working for VLAN 3 (only works for VLAN 2)

Could someone please help me?.

Best Regards

This is a capture with Wireshark. It seens like DHCP server gives 192.168.30.3.

No.     Time        Source                Destination           Protocol Length Info
      1 0.000000    0.0.0.0               255.255.255.255       DHCP     342    DHCP Discover - Transaction ID 0x61cd03c

Frame 1: 342 bytes on wire (2736 bits), 342 bytes captured (2736 bits)
Ethernet II, Src: DellInc_af:34:52 (00:15:c5:af:34:52), Dst: Broadcast (ff:ff:ff:ff:ff:ff)
Internet Protocol Version 4, Src: 0.0.0.0 (0.0.0.0), Dst: 255.255.255.255 (255.255.255.255)
User Datagram Protocol, Src Port: 68 (68), Dst Port: 67 (67)
Bootstrap Protocol (Discover)
    Message type: Boot Request (1)
    Hardware type: Ethernet (0x01)
    Hardware address length: 6
    Hops: 0
    Transaction ID: 0x061cd03c
    Seconds elapsed: 0
    Bootp flags: 0x0000 (Unicast)
        0... .... .... .... = Broadcast flag: Unicast
        .000 0000 0000 0000 = Reserved flags: 0x0000
    Client IP address: 0.0.0.0 (0.0.0.0)
    Your (client) IP address: 0.0.0.0 (0.0.0.0)
    Next server IP address: 0.0.0.0 (0.0.0.0)
    Relay agent IP address: 0.0.0.0 (0.0.0.0)
    Client MAC address: DellInc_af:34:52 (00:15:c5:af:34:52)
    Client hardware address padding: 00000000000000000000
    Server host name not given
    Boot file name not given
    Magic cookie: DHCP
    Option: (53) DHCP Message Type (Discover)
        Length: 1
        DHCP: Discover (1)
    Option: (116) DHCP Auto-Configuration
        Length: 1
        DHCP Auto-Configuration: AutoConfigure (1)
    Option: (61) Client identifier
        Length: 7
        Hardware type: Ethernet (0x01)
        Client MAC address: DellInc_af:34:52 (00:15:c5:af:34:52)
    Option: (50) Requested IP Address
        Length: 4
        Requested IP Address: 169.254.168.171 (169.254.168.171)
    Option: (12) Host Name
        Length: 8
        Host Name: D1MBXN2J
    Option: (60) Vendor class identifier
        Length: 8
        Vendor class identifier: MSFT 5.0
    Option: (55) Parameter Request List
        Length: 11
        Parameter Request List Item: (1) Subnet Mask
        Parameter Request List Item: (15) Domain Name
        Parameter Request List Item: (3) Router
        Parameter Request List Item: (6) Domain Name Server
        Parameter Request List Item: (44) NetBIOS over TCP/IP Name Server
        Parameter Request List Item: (46) NetBIOS over TCP/IP Node Type
        Parameter Request List Item: (47) NetBIOS over TCP/IP Scope
        Parameter Request List Item: (31) Perform Router Discover
        Parameter Request List Item: (33) Static Route
        Parameter Request List Item: (249) Private/Classless Static Route (Microsoft)
        Parameter Request List Item: (43) Vendor-Specific Information
    Option: (43) Vendor-Specific Information
        Length: 2
        Value: dc00
    Option: (255) End
        Option End: 255
    Padding

No.     Time        Source                Destination           Protocol Length Info
      2 0.001156    192.168.20.200         192.168.30.201         DHCP     342    DHCP Offer    - Transaction ID 0x61cd03c

Frame 2: 342 bytes on wire (2736 bits), 342 bytes captured (2736 bits)
Ethernet II, Src: HewlettP_16:ce:8e (00:24:81:16:ce:8e), Dst: HewlettP_0a:f1:c0 (38:63:bb:0a:f1:c0)
Internet Protocol Version 4, Src: 192.168.20.200 (192.168.20.200), Dst: 192.168.30.201 (192.168.30.201)
User Datagram Protocol, Src Port: 67 (67), Dst Port: 67 (67)
Bootstrap Protocol (Offer)
    Message type: Boot Reply (2)
    Hardware type: Ethernet (0x01)
    Hardware address length: 6
    Hops: 0
    Transaction ID: 0x061cd03c
    Seconds elapsed: 0
    Bootp flags: 0x0000 (Unicast)
        0... .... .... .... = Broadcast flag: Unicast
        .000 0000 0000 0000 = Reserved flags: 0x0000
    Client IP address: 0.0.0.0 (0.0.0.0)
    Your (client) IP address: 192.168.30.3 (192.168.30.3)
    Next server IP address: 192.168.20.200 (192.168.20.200)
    Relay agent IP address: 192.168.30.201 (192.168.30.201)
    Client MAC address: DellInc_af:34:52 (00:15:c5:af:34:52)
    Client hardware address padding: 00000000000000000000
    Server host name not given
    Boot file name not given
    Magic cookie: DHCP
    Option: (53) DHCP Message Type (Offer)
        Length: 1
        DHCP: Offer (2)
    Option: (1) Subnet Mask
        Length: 4
        Subnet Mask: 255.255.255.0 (255.255.255.0)
    Option: (58) Renewal Time Value
        Length: 4
        Renewal Time Value: (345600s) 4 days
    Option: (59) Rebinding Time Value
        Length: 4
        Rebinding Time Value: (604800s) 7 days
    Option: (51) IP Address Lease Time
        Length: 4
        IP Address Lease Time: (691200s) 8 days
    Option: (54) DHCP Server Identifier
        Length: 4
        DHCP Server Identifier: 192.168.20.200 (192.168.20.200)
    Option: (3) Router
        Length: 4
        Router: 192.168.30.1 (192.168.30.1)
    Option: (82) Agent Information Option
        Length: 12
        Option 82 Suboption: (1) Agent Circuit ID
            Length: 2
            Agent Circuit ID: 001c
        Option 82 Suboption: (2) Agent Remote ID
            Length: 6
            Agent Remote ID: 3863bb0af1c0
    Option: (255) End
        Option End: 255
    Padding

On the relay, play around with option 82 setting.  You also might look for option so dhcp relay uses broadcast L3 address instead of offered IP address in DHCP-Offer packet header