DHCP Setup across multiple VLANs on RV325 - DHCP Server only working on VLAN 1

[david.dunaway]

I have multiple VLAN subnets defined on my RV325 - when I try and utilize a DHCP Server on each VLAN, it only seems to be issuing IP Addresses to clients on VLAN ID 1.  When I first set this up months ago, I thought I had tested it providing IP Addresses via the other subnets.  Now that I am trying to do so, it isn't working "as expected".  Example - I am using VLAN 25 as the GuestWireless subnet utilizing a separate 802.11n WAP that is set to Bridge connections to the IP Address of the VLAN interface.  Devices are able to connect to the WAP, but end up with a self-assigned IP Address 169.x.x.x address.  There has to be an easy fix to this, but I seem to be "stuck" figuring out what it is…pointers/redirects appreciated.  Thanks!

[SANTHOSHKUMAR SARAVANAN]

Hi , 

 Look into below url for your requirement . on page no 45

http://www.cisco.com/c/dam/en/us/td/docs/routers/csbr/rv320/administration/guide/en/rv32x_ag_en.pdf

Configuring DHCP for IPv4
To configure DHCP for IPv4:
STEP 1 Choose VLAN or Option 82.
STEP 2 If you choose Option 82, add circuit IDs by using DHCP > Option 82. Those circuit 
IDs are then listed in the Circuit ID drop-down menu.
If you choose VLAN, select the VLAN from the VLAN ID menu and enter:
• Device IP Address—Management IP address.
• Subnet Mask—Management IP subnetwork mask.
STEP 3 Select the DHCP Mode:
• Disable—Disables DHCP on this device. There are no additional parameters 
to complete.
• DHCP Server—Communicates the client DHCP requests to the device 
DHCP server. 
• DHCP Relay—Passes DHCP requests and replies from another DHCP 
server through the device. If DHCP Relay is chosen, enter the Remote DHCP 
Server IP address.DHCP
DHCP Setup
Cisco Small Business RV320/RV325 Administration Guide 47
4 
• Client Lease Time—Amount of time in minutes that a network user is 
allowed to connect to the router with the current IP address. Valid values are 
5 to 43200 minutes. The default is 1440 minutes (equal to 24 hours). 
• Range Start and Range End—Starting and ending IP addresses that create 
a range of IP addresses that can be assigned dynamically. The range can be 
up to the maximum number of IP addresses that the server can assign 
without overlapping features such as PPTP and SSL VPN . Do not include this 
device LAN IP address in this dynamic IP range. For example, if the router 
uses the default LAN IP address, 192.168.1.1, the starting value must be 
192.168.1.2 or greater. 
• DNS Server—DNS service type; where the DNS server IP address is 
acquired.
• Static DNS 1 and Static DNS 2—Static IP address of a DNS Server. 
(Optionally) if you enter a second DNS server, the device uses the first DNS 
server to respond to a request. 
• WINS—Optional IP address of a Windows Internet Naming Service (WINS) 
server that resolves NetBIOS names to IP addresses. If you do not know the 
IP address of the WINS server, use the default, 0.0.0.0.

HTH

Sandy

[david.dunaway]

Thanks - I've already reviewed that information before I posted.  I've been working with DHCP since the mid-90's, so I'm comfortable with the settings/configuration I need to leverage to make this work via other means using various Network-based OSes.

I'm wondering if there are other options in configuring this device that can impact the ability to dynamically serve IP addresses on a VLAN/subnet-by-VLAN/subnet basis.

As I did more testing, I discovered when I reserved an IP Address via the IP & MAC Binding option within the DHCP Settings, those devices would receive their static reservations and work as expected, so the problem seems to be leveraging the DHCP Pool for devices connecting to VLANs other that VLAN 1.

Any ideas as to why the DHCP Pool's are "non-functioning" for the other VLANs is greatly appreciated...

Each VLAN is setup with a separate DHCP Server configuration as shown below:

VLAN ID = 1 (Default, Inter VLAN Routing = Enabled, LAN1-6 = Untagged, LAN7=Tagged, LAN8=Excluded, LAN9-14 Untagged)
Device IP Address = 172.16.xxx.1
Subnet Mask = 255.255.255.0
DHCP Mode = DHCP Server
Remote DHCP Server = 0.0.0.0
Client Lease Time = 1440 min
Range Start = 172.16.xxx.100
Range End = 172.16.xxx.199
DNS Server = Use DNS as Below
Static DNS 1 = 208.67.222.222
Static DNS 2 = 208.67.220.220
WINS Server = 0.0.0.0

Correctly serving IP Addresses via DHCP (both static and dynamic) to Wired devices & Wireless devices connecting through WAP (set to Bridge)

VLAN ID = 25 (GuestWireless, Inter VLAN Routing = Disabled, LAN1-LAN7 = Excluded, LAN8 = Untagged, LAN9-14 = Excluded)
Device IP Address = 172.16.yyy.1
Subnet Mask = 255.255.255.0
DHCP Mode = DHCP Server
Remote DHCP Server = 0.0.0.0
Client Lease Time = 1440 min
Range Start = 172.16.yyy.100
Range End = 172.16.yyy.199
DNS Server = Use DNS as Below
Static DNS 1 = 208.67.222.222
Static DNS 2 = 208.67.220.220
WINS Server = 0.0.0.0

NOT serving dynamic IP Addresses via DHCP to Wired devices & Wireless devices connecting through WAP (set to Bridge)
Static DHCP Reservations setup via IP & MAC Binding settings DO WORK in terms of providing the assigned static IP Address to the client.  Inbound/Outbound traffic to Internet works for devices with Static DHCP Reservations.

VLAN ID = 100 (Voice, Inter VLAN Routing = Disabled, LAN1-6 Excluded, LAN7 = Untagged, LAN8-14 = Excluded)
Device IP Address = 192.168.zzz.1
Subnet Mask = 255.255.255.0
DHCP Mode = DHCP Server
Remote DHCP Server = 0.0.0.0
Client Lease Time = 1440 min
Range Start = 192.168.zzz.100
Range End = 192.168.zzz.199
DNS Server = Use DNS as Below
Static DNS 1 = 208.67.222.222
Static DNS 2 = 208.67.220.220
WINS Server = 0.0.0.0

NOT serving dynamic IP Addresses via DHCP to Wired devices & Wireless devices connecting through WAP set to Bridge
Static DHCP Reservations setup via IP & MAC Binding settings DO WORK in terms of providing the assigned static IP Address to the client.  Inbound/Outbound traffic to Internet works for devices with Static DHCP Reservations.

[grodgers2]

I have the same issue.  Only the DCHP server on VLAN 1 seems to issue addresses.  I have upgraded to firmware 1.1.1.06 in hopes that it fixes this, to no avail.

[david.dunaway]

I've been running that firmware since the day I deployed, so unfortunately, that won't fix the issue…this isn't covered in any of the Known Issues section within Cisco's documentation…How do we get them to acknowledge that this isn't working as expected???

[david.dunaway]

I have opened up a support case w/Cisco - will report back with findings/resolution.

[Arxh-2014]

You may have solved your problem since.

Configuration vlan 1 (default vlan) is untagged, which means that if a computer or an unconfigured switch (just the default vlan) is connected directly above the RV325 router will put the pc or switch in VLAN 1.


We must create a vlan 2 for example on the router and configure the switch or pc on vlan 2 (in the device manager / parameter of the ethernet card) and then the router will assign the correct IP.

[ryanblack1]

That's exactly what my issue was. Vlan1 all ports were untagged so it was hijacking anything I plugged into any port, even though DHCP was turned off for Vlan1.  Once I set most of Vlan1's ports to excluded and setup my other vlans with their port range, it is now dishing the correct IP's on the correct ports.  Cisco and their Vlan's.....

[glynne491]

Ryan,

I am having a similar problem where I have a windows server on vlan 1 servicing DHCP and I am trying to get an RV325 to issue IP addresses via DHCP on vlan 20.  Other than the Internet connection I only have one wire coming off the RV325 and it connects between port 12 of the router and port 1 of a Cisco SG300-52 switch.  DHCP for vlan1 (subnet 16) is turned off on the router but DHCP for vlan20 (subnet 20) on the router is turned on and configured.  Router ports are set as follows Port 1-11 and 13-14: Vlan1=Untagged, Vlan20=Excluded, Port 12: Vlan1=Untagged, Vlan20=Tagged.  Switch port 1: Vlan1=Untagged, Vlan20=Tagged, Switch port 4: Vlan1=Untagged, Vlan20=Tagged (the WAP is tied to switch port 4).   I think I am hearing that I should modify my tagging on the router but what should I change the unused ports to.  I am being told by Cisco that in order for DHCP to work for Vlan20 that it must be turned on for Vlan1, which is really hard for me to understand why.  All works well with Subnet 16 but the router simply will not service DHCP for subnet 20.

[cchamorr]

Hello,

I think the issue is related to the fact that in most Small Business routers, if you disable DHCP on VLAN 1 then it gets disabled for any other VLAN. You can disable it in other other VLAN but not in VLAN 1.

Now Since you have a SG300, you could use that switch to provide DHCP for VLAN 20 which the switch is perfectly capable of doing.

I hope this was helpful.

[ryanblack1]

"Hello,

I think the issue is related to the fact that in most Small Business routers, if you disable DHCP on VLAN 1 then it gets disabled for any other VLAN. You can disable it in other other VLAN but not in VLAN 1.

Now Since you have a SG300, you could use that switch to provide DHCP for VLAN 20 which the switch is perfectly capable of doing.

I hope this was helpful."

This is my understanding as well. Vlan1 will always be in effect for these small business routers.  I keep mine with DHCP on and assign it to a single unused port.  I can see two options for you.

1. Re-create subnet 16 on a new vlan.  Give Vlan1 an arbitrary subnet, turn on DHCP and assign it to port 1.  Then you know Vlan1 is always on port 1.  Since port 1 is also used for any port mirroring, this helps keep it separate as well.

2. Continue to use Vlan1 for Subnet 16, turn on DHCP and set the range to not include the address's you are already using and add your used address's to the excluded list.

Either way, I believe you will have to turn DHCP on for Vlan1.  I ended up returning my RV325 for a list of other issues as well and went with the SG300 switch to replace it.  Very happy with my decision. 

[cchamorr]

Hello, 

The issue is that when you disable DHCP on VLAN 1 you are disabling the service itself and then DHCP will no longer work on any other VLAN.

I used the following workaround before with other user and it worked just fine to allow for the same type of setup you are using now.

As a work around to use the router as DHCP server for VLAN 2, you could enable the DHCP server on the router for VLAN 1, leave it 2 IP addresses available, lets say from 192.168.1.253 to 192.168.1.254, then go to Static DHCP under Networking and the LAN and bind two phony mac addresses to those two IP addresses so they won't be assigned to any devices. This way you will still be able to use your DHCP server without having to disable the DHCP server from the router.

Please try the above mentioned option and let us know it it works for you.

It would be greatly appreciated if you let us know what happens.

[Net_Connect473]

I have found on the RV320 that if I assign a MAC to an IP that is outside the reservation range for a VLAN that DHCP stops handing out IP's on that VLAN.