SG300 : erreurs de DHCP

Bonjour,
J'ai plusieurs switchs SG300-20 et SG300-10 en cascades avec une topologie qui ressemble à ceci :
SW0 => SW2 : connexion par trois liens en LACP
SW1 => SW2 : connexion par un seul lien
SW3 => SW2 : connexion par trois liens en LACP
SW4 => SW2 : connexion par un seul lien
J'ai des PC connectés sur tous les switchs.
Mon serveur DHCP est connecté sur SW2. Le port est en trust et le DHCP snooping activé. Dans tous les switchs j'ai activé le relai DHCP avec l'adresse IP du serveur DHCP.
Malheureusement, j'ai des erreurs qui arrivent sur SW2 :
%DHCPSNOOP-E-HDRMAC: DHCP packet mac addresses verification problem - packet dropped: vlan - 20, port - Po2, mac source address - <ADRESSE_MAC_DE_SW0>, mac dest ad dress - <ADRESSE_MAC_DU_SERVEUR_DHCP>, hw client address - <ADRESSE_MAC_D_UN_POSTE_CLIENT>, error - DHCPSnP_packet_callback
J'ai donc plusieurs questions :
- est-ce que quelqu'un sait d'où viennent ces erreurs ? Je les ai tous les jours
- est-ce qu'il faut activer le relai DHCP sur tous les switchs ou seulement SW2 puisque le serveur DHCP est dessus ?
- est-ce qu'il faut activer le relai DHCP + DHCP snooping comme je l'ai fait ?
Je vous remercie d'avance.
Bertrand

Tom,
Thanks ... I followed the steps you outlined and it worked! The only difference being that I have an Asus RT-AC66U router and the there is no "enable multiple subnet" option. So, I just followed your instructions on creating the static routes in the RT-AC66U and everything worked. The DHCP addresses were correct and I had internet connectivity when I plugged a laptop into the gi8 port.
I did make one tweak to the Network Pools screen as follows:
My DHCP configuration for gi8 on VLAN 2 now looks like:
ip dhcp server
ip dhcp pool network InternalWAN
address low 192.168.2.1 high 192.168.2.99 255.255.255.0
lease infinite
domain-name MYSTIC
default-router 192.168.2.254
dns-server 8.8.8.8
Previously I had followed your advice in the article "Need help configuring SG300-10 switch" and had setup everything using CLI. However, I didn't think about needing the static routes. So, I think it was probably setup correctly beforehand but had no chance to work because the routes were not setup.
Thanks very much for your help!
Clint

Similar Messages

SG300 and RVS4000 DHCP problems

We recently deployed SG300-28 to replace an old 3Com switch.
The setup:
RVS400 router and all workstations and server are plugged into the SG300 switch.
The problem:
Windows 7 workstations are unable to obtain IP addresses from the server which is also plugged into the switch.
If however, we plug in the worstations into the 4 port switch on the back of the RVS4000 (the router), they get IPs from the server no problem.
This worked just fine with the old 3Com switch so we filed it under the Small Business Switches category.
Any comments/tips appreciated! Thanks in advance!
Pavol

Pavol,
Please make sure the SG300 switch is running latest firmware 1.1.2.0 , also this is new code so please factory reset the switch after the upgrade. If you need assistance in upgrading please call Cisco Small Business Support Center @ 1-866-606-1866
After the upgrade please repost how these devices are connected and the configuration of your RVS4000 & SG300 series switch. Are you using RVS4000 for your DHCP server?
Also make sure your RVS4000 is running latest firmware as well.
Jasbryan

SG300-20 - Configure DHCP on VLAN interface

I have been reading the various related discussions on the SG300 and SG500 switches regarding setting up VLAN's and DHCP on those VLAN's. For whatever reason I have been unable to even get this simple task to work.
First thing I did was to update my firmware and boot version as follows:
SW version    1.3.7.18 ( date 12-Jan-2014 time 18:02:59 )
Boot version    1.3.5.06 ( date 21-Jul-2013 time 15:12:10 )
HW version    V02
When I reloaded the SG300 after the SW/Boot updates the startup config was wiped out and I had to setup my switch from scratch. The intent is to have two VLAN's:
VLAN 1: all devices, servers, etc.
VLAN 2: basic subnet that hands out DHCP addresses
The SG300-20 is connected to an Asus RT-AC66U router on the 192.168.1.x subnet and provides internal network access and WiFi access (router IP address is 192.168.1.1 and is default gateway). All that works with no issues. So my task is simply to create VLAN 2 on 192.168.2.x subnet and use DHCP to allocate addresses. I have spent many hours on this and I still can't get it to work. When I connect a laptop to the port (GI8) assigned to VLAN 2, I end up getting some wonky 169.254.x.x address. I certainly thought something this "easy" wouldn't be that hard to setup, but apparently I was wrong.
The SG300 is running in L3 mode as shown in my running-config below.
Does anyone happen to see something that might be preventing my laptop client from recieving IP addresses from the VLAN 2 DHCP interface that are not in the 192.168.2.x subnet?
Any ideas / suggestions would be greatly appreciated!
Here's my running-config:
config-file-header
MYSTICSW1
v1.3.7.18 / R750_NIK_1_35_647_358
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 2
exit
voice vlan oui-table add 0001e3 Siemens_AG_phone________
voice vlan oui-table add 00036b Cisco_phone_____________
voice vlan oui-table add 00096e Avaya___________________
voice vlan oui-table add 000fe2 H3C_Aolynk______________
voice vlan oui-table add 0060b9 Philips_and_NEC_AG_phone
voice vlan oui-table add 00d01e Pingtel_phone___________
voice vlan oui-table add 00e075 Polycom/Veritel_phone___
voice vlan oui-table add 00e0bb 3Com_phone______________
bonjour interface range vlan 1
hostname MYSTICSW1
logging host 192.168.1.15
logging origin-id hostname
username cisco password encrypted b4a0fcf20b2cd9d80a55b06ab8f83277f9733904 privilege 15
snmp-server location Office
clock timezone " " -5
clock summer-time web recurring usa
clock source sntp
sntp unicast client enable
sntp unicast client poll
sntp server 192.168.1.10 poll
interface vlan 1
ip address 192.168.1.254 255.255.255.0
no ip address dhcp
interface vlan 2
name MysticWAN
ip address 192.168.2.254 255.255.255.0
interface gigabitethernet8
switchport mode access
switchport access vlan 2
exit
ip default-gateway 192.168.1.1
Thanks in advance!
Clint Lambert

Tom,
Thanks ... I followed the steps you outlined and it worked! The only difference being that I have an Asus RT-AC66U router and the there is no "enable multiple subnet" option. So, I just followed your instructions on creating the static routes in the RT-AC66U and everything worked. The DHCP addresses were correct and I had internet connectivity when I plugged a laptop into the gi8 port.
I did make one tweak to the Network Pools screen as follows:
My DHCP configuration for gi8 on VLAN 2 now looks like:
ip dhcp server
ip dhcp pool network InternalWAN
address low 192.168.2.1 high 192.168.2.99 255.255.255.0
lease infinite
domain-name MYSTIC
default-router 192.168.2.254
dns-server 8.8.8.8
Previously I had followed your advice in the article "Need help configuring SG300-10 switch" and had setup everything using CLI. However, I didn't think about needing the static routes. So, I think it was probably setup correctly beforehand but had no chance to work because the routes were not setup.
Thanks very much for your help!
Clint

SGE2000 - SG300 - MGBLH1 - Connectivity/DHCP/VLAN

Hi Experts,
Need your help, advise and support to fix the below issue in bringing our network
Just extended our intranet buildings with Fiber Optic Connectivity with the Following Components
Data Center Building
1. SG2000 - CISCO
2. 24 port LIU - MOLEX
3. GBIC SFP Transceiver - single mode SG300 MGBLH1 - CISCO
New Building with OFC Terminated
1. SG300 Switch SG300-28P (SRW2024P-K9) - CISCO
2. 24 port LIU - MOLEX
3. GBIC SFP Transceiver - single mode SG300 MGBLH1 - CISCO
Post the OFC Termination and Splicing, we are able to get the Link and connectivity through the SFP Ports.
But unable to get the Ethernet Link up and running.
SG2000 is configured to be L3 Mode Switch with couple of VLAN configurations and working perfectly well.
Have configured one of the custom VLAN in the new building and made the DHCP Relay to be passed through, but it is not passing the DHCP traffic.
But peculiarly, when we connect both the ends with SG300, it works like a charm.
Hence, i went back to basics and checked the SFP compatibility, and alas, the MBGLH1 is compatible with SG2000
Please advise, what additional should be made to extend the network with the above setup.

Hi.,
I am sorry for delayed reply.
This issue has been addressed and fixed. To update what the issue was.
1. When we connected the SFP Ports to the corresponding locations, link was up but it did get pass traffic through, as I was tailing my DHCP server logs.
2. My ex-colleague helped me to understand, though the SFP ports are separate on this Switch(SG300), the moment we connect a SFP port, one of the ethernet port which lits up has to be configured to our requirements.
3. I had allowed the corresponding Gig port g/11 to allow the specific vlan and enabled the dhcp relay option. It started receiving the traffic on the DHCP Server.
One more Issue was: Only Ports g/11 and g/23 were working out of the Four SFP ports.
While troubleshooting, sh interface commands showed the g/12 and g/24 as blank, and after 3 hours of continuous amateur troubleshooting,
When logged into the GUI mode of the switch and clicked on the port g/12 in the status page, it threw an error stating, that "This is a stacking port and cannot be configured".
Then I disabled the Stacking mode and had to reload the switch to make it work.
It was really an awesome learning and was very interesting to do such stuff.
I am sorry if something were very basic things which I should have done and missed it. Forgive me as I am a system administrator who has deep interests in working with networking.
Please help as I may be posting many other questions like this as I am volunteering my time and support to a non profit organization.
Way to go !!!

Dhcp status are not received on sg300-20

Hello,
I am configuring vlan on sg300-20 in dhcp mode.
One vlan (5) that is directed connected to the adsl router get ip address and when I connect host to the ports in this vlan they also receive ip address and can go on internet.
The other four vlans dhcp status are not received
Kindly help me check this. Thanks
switch4ba497#sh running-config
config-file-header
switch4ba497
v1.2.9.44 / R750_NIK_1_2_584_002
CLI v1.0
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 5,10,20,30,40
exit
voice vlan oui-table add 0001e3 Siemens_AG_phone________
voice vlan oui-table add 00036b Cisco_phone_____________
voice vlan oui-table add 00096e Avaya___________________
voice vlan oui-table add 000fe2 H3C_Aolynk______________
voice vlan oui-table add 0060b9 Philips_and_NEC_AG_phone
voice vlan oui-table add 00d01e Pingtel_phone___________
voice vlan oui-table add 00e075 Polycom/Veritel_phone___
voice vlan oui-table add 00e0bb 3Com_phone______________
ip dhcp relay address 192.168.3.1
ip dhcp information option
no boot host auto-config
bonjour interface range vlan 1
hostname switch4ba497
line telnet
exec-timeout 0
exit
no passwords complexity enable
username cisco password encrypted 7af78c911d5b48bea1dc2449d9d89513abeb4be5 privilege
15
ip http timeout-policy 0 http-only
ip name-server 192.168.1.1 192.168.3.1
ip telnet server
interface vlan 1
ip address 192.168.2.254 255.255.255.0
no ip address dhcp
interface vlan 5
name WAN
ip address dhcp
interface vlan 10
name Studio
ip address dhcp
interface vlan 20
name Service
ip address dhcp
interface vlan 30
name Admin
ip address dhcp
interface vlan 40
name Data
ip address dhcp
interface gigabitethernet1
switchport mode access
interface gigabitethernet2
switchport mode access
switchport access vlan 10
interface gigabitethernet3
switchport mode access
switchport access vlan 10
interface gigabitethernet4
switchport mode access
switchport access vlan 10
interface gigabitethernet5
switchport mode access
switchport access vlan 10
interface gigabitethernet6
switchport mode access
switchport access vlan 10
interface gigabitethernet7
switchport mode access
switchport access vlan 10
interface gigabitethernet8
switchport mode access
interface gigabitethernet9
switchport mode access
switchport access vlan 20
interface gigabitethernet10
switchport mode access
switchport access vlan 20
interface gigabitethernet11
switchport mode access
switchport access vlan 20
interface gigabitethernet12
switchport mode access
switchport access vlan 20
interface gigabitethernet13
switchport mode access
switchport access vlan 30
interface gigabitethernet14
switchport mode access
switchport access vlan 30
interface gigabitethernet15
switchport mode access
switchport access vlan 30
interface gigabitethernet16
switchport mode access
switchport access vlan 30
interface gigabitethernet17
switchport mode access
interface gigabitethernet18
switchport trunk native vlan 40
interface gigabitethernet19
switchport mode access
switchport access vlan 5
interface gigabitethernet20
switchport trunk native vlan 5
switch4ba497#sh ip int
    IP Address         I/F       Type     Directed   Precedence   Status
                                          Broadcast
0.0.0.0/32          vlan 10   DHCP        disable    No         Not
                                                                received
0.0.0.0/32          vlan 20   DHCP        disable    No         Not
                                                                received
0.0.0.0/32          vlan 30   DHCP        disable    No         Not
                                                                received
0.0.0.0/32          vlan 40   DHCP        disable    No         Not
                                                                received
192.168.2.254/24    vlan 1    Static      disable    No         Valid
192.168.3.102/24    vlan 5    DHCP        disable    No         Valid
switch4ba497#
I also do not understand why the ip address is 0.0.0.0/32.
Becuase the dhcp address 192.168.3.1/24
Thanks.

Hello Tom,
Yes i can feel you taking me toward the solution.
Actually I have an ADSL router that has DHCP capability and my vlan interfaces are to receive ip address from it.
The adsl router Ip address is 192.168.3.1
Vlan 5 WAN which is directly connected to the adsl router get Ip address while the other vlan do not.
When I assign port from other vlan to vlan 5 and I attach host to the port they get ip address and go on internet. The strange thing is that the other vlan do not get ip address. Thanks.

SG300 with WAP551 VLAN DHCP confusion

Cisco Small Business Pros,
I need a hand. I am trying to configure 2 seperate vlans for a WAP551 in unique broadcast address spaces. I have been able to configure the WAP551 and was planning on letting a SG300 handle the DHCP. On the SG300 I have configured two different DHCP pools but there does not seem to be a way to specify an associated VLAN. Am I thinking about this wrong? How do I get VLAN1 to pull from 192.168.1.2/24 and VLAN2 to pull from 192.168.2.2/24?
Sincerely,
Dennison

Hi,
Unfortunately there is a change and this behavior will be corrected in the next release. In the meantime you may try the following workarounds:
1.
1) Disable Voice VLAN on port
2) Toggle port status (link down and then up)
3) Enable Voice VLAN on port once again
2. or use 1.3.5 firmware
Please feel free to open ticket with Small Business Team if you would like to get some information or share some comments.
Regards,
Aleksandra

Vlans dhcp status are not received

Hello,
I am configuring vlan on sg300-20 in dhcp mode.
One vlan that is directed connected to the adsl router get ip address and when I connect host to the ports in this vlan they also receive ip address and can go on internet.
The other four vlans dhcp status are not received.
Kindly help me check this. Thanks
Below is the config log:
switch4ba497#sh running-config
config-file-header
switch4ba497
v1.2.9.44 / R750_NIK_1_2_584_002
CLI v1.0
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 5,10,20,30,40
exit
voice vlan oui-table add 0001e3 Siemens_AG_phone________
voice vlan oui-table add 00036b Cisco_phone_____________
voice vlan oui-table add 00096e Avaya___________________
voice vlan oui-table add 000fe2 H3C_Aolynk______________
voice vlan oui-table add 0060b9 Philips_and_NEC_AG_phone
voice vlan oui-table add 00d01e Pingtel_phone___________
voice vlan oui-table add 00e075 Polycom/Veritel_phone___
voice vlan oui-table add 00e0bb 3Com_phone______________
ip dhcp relay address 192.168.3.1
ip dhcp information option
no boot host auto-config
bonjour interface range vlan 1
hostname switch4ba497
line telnet
exec-timeout 0
exit
no passwords complexity enable
username cisco password encrypted 7af78c911d5b48bea1dc2449d9d89513abeb4be5 privilege
15
ip http timeout-policy 0 http-only
ip name-server 192.168.1.1 192.168.3.1
ip telnet server
interface vlan 1
ip address 192.168.2.254 255.255.255.0
no ip address dhcp
interface vlan 5
name WAN
ip address dhcp
interface vlan 10
name Studio
ip address dhcp
interface vlan 20
name Service
ip address dhcp
interface vlan 30
name Admin
ip address dhcp
interface vlan 40
name Data
ip address dhcp
interface gigabitethernet1
switchport mode access
interface gigabitethernet2
switchport mode access
switchport access vlan 10
interface gigabitethernet3
switchport mode access
switchport access vlan 10
interface gigabitethernet4
switchport mode access
switchport access vlan 10
interface gigabitethernet5
switchport mode access
switchport access vlan 10
interface gigabitethernet6
switchport mode access
switchport access vlan 10
interface gigabitethernet7
switchport mode access
switchport access vlan 10
interface gigabitethernet8
switchport mode access
interface gigabitethernet9
switchport mode access
switchport access vlan 20
interface gigabitethernet10
switchport mode access
switchport access vlan 20
interface gigabitethernet11
switchport mode access
switchport access vlan 20
interface gigabitethernet12
switchport mode access
switchport access vlan 20
interface gigabitethernet13
switchport mode access
switchport access vlan 30
interface gigabitethernet14
switchport mode access
switchport access vlan 30
interface gigabitethernet15
switchport mode access
switchport access vlan 30
interface gigabitethernet16
switchport mode access
switchport access vlan 30
interface gigabitethernet17
switchport mode access
interface gigabitethernet18
switchport trunk native vlan 40
interface gigabitethernet19
switchport mode access
switchport access vlan 5
interface gigabitethernet20
switchport trunk native vlan 5
switch4ba497#sh ip int
    IP Address         I/F       Type     Directed   Precedence   Status
                                          Broadcast
0.0.0.0/32          vlan 10   DHCP        disable    No         Not
                                                                received
0.0.0.0/32          vlan 20   DHCP        disable    No         Not
                                                                received
0.0.0.0/32          vlan 30   DHCP        disable    No         Not
                                                                received
0.0.0.0/32          vlan 40   DHCP        disable    No         Not
                                                                received
192.168.2.254/24    vlan 1    Static      disable    No         Valid
192.168.3.102/24    vlan 5    DHCP        disable    No         Valid
switch4ba497#
Also i do not understand why the ip address is 0.0.0.0/32 because the dhcp server ip address is 192.168.3.1

Dear Customer,
Thank you for reaching Small Business Support Community.
In Layer 2 system mode, only the management VLAN can be configured with a static or dynamic IP address. In Layer 3 system mode, all the interface types (ports,LAGs, and/or VLANs) on the device can be configured with a static or dynamic IP. Configuring the device to work in either mode is performed in the Administration >System Settings page
When a DCHP Client starts a discovery process, it assigns a dummy IP address 0.0.0.0 before the real address is obtained. This dummy address has the status of “Not Received”.
Pretty much your problem should be solved by changing to Layer3 system mode. Please let me know if anything comes up and/or if there is any further assistance I may help you with.
Kind regards,
Jeffrey Rodriguez S. .:|:.:|:.
Cisco Customer Support Engineer
*Please rate the Post so other will know when an answer has been found.

SG300 with 2 WAN devices

Hello there all,
I have a couple of questions hoping someone could tell me how to make it work:
The following situation in my home right now:
1) Fiber coming into my home (other side is a Cisco 2911 router with both internet and my own ip adresses)
This is right now directly connected to the SG300 switch (L2) i have at home
2) I however also have a normal 100mbit cable connection at home, a Cisco EPC3925 modem/router.
I was thinking of, in some way maybe making a local network where it could either use both connections or use one as backup, when the other goes down for within my home. Ofc all devices on my local LAN need to be able to connect to the internet.
Is there a way at all to make this work? And if so, how do i need to configure the SG300 (maybe enable DHCP/L3?) and do i then need to disable DHCP on the 2911 and/or the cable router/modem?
What is possible?

Hi Michiel,
If you are wanting to use two different connections one method would be to have the connections come into the switch on two different VLANs and then have those two different VLANs each go to a different router. When one connection goes down you could connect to the next one.
If you are wanting to use them on the same connection you could use DualWAN router.
Best Regards,
Trevor Rietcheck

SG300-28P Multicast (IGMP) and IGMP routing..

A brief background on the setup:
I recently switched out my switch. It was a Cisco 3750 10/100 switch and I wanted to upgrade to Gig. The cost of a Gig+POE 3750 is too much to bite so I opted for the SG300. My router is a Cisco 891. Here is the setup:
Cisco 891:
two SVI's: vlan1 and vlan 100
Vlan1 = 10.0.1.1/24
Vlan100 = 10.0.100.2/24
Connected to SG300 via Fa0
DHCP Server for vlan1+vlan100
Cisco SG300-28P:
two SVI's: vlan 1 and vlan 100
vlan 1 = 10.0.1.21/24
vlan 100 = 10.0.100.1/24
Connected to 891 on via Gi18
The connection between 891 and SG300 = trunk, vlan1-u, vlan100-t
The problem:
With the 891+3750, I was able to add "ip pim sparse-dense-mode" on all the SVI's and hosts could join any multicast group, irregardless of which vlan the host was a member of.
Now I've changed switches, and I dont get the same love. I have the PIM statement on both SVI's on the 891, but Im unsure of what I need to configure on the SG300. I have enabled "Bridge multicast filtering" + "IGMP snooping". What can I do to get similar functionality using the SG300 + 891? I assume this is my lack of understanding IGMP in general, but was able to get away with it using the PIM statements on the 891+3750 stack.
Jeff

You should be able to filter unregisted multicast on every port.
To be able to pass multicast over subnets two things must be certain, the node/device is able to send and receive multicast packets but also register the multicast address being listened to by the node so the local and remote routers can route the multicast packets.
When the switch learns a multicast address through IGMP snooping, this is a registered multicast. The switch will only forward multicast to ports that are registered to the multicast group. Where unregistered multicast comes in, is the multicast that is not statically defined or learned through IGMP which in turn will be forwarded to all ports of the vlan.

Two questions about SG300 DHCP server

Hi,
I have two questions about the DHCP server on the SG300:
On the Address Binding page, what does the "Declined" state mean? I have a NAS device that won't pull an address, and I think that the entry with a state of "Declined" corresponds to this device. It was previously pulling an address from a RV180, so the only difference is that it is now connected to the SG300. I worked around this by manually setting the address on the NAS device, but this won't scale if I run into a lot of other devices that can't pull an address.
I configured a static address binding for a WAP321 and found that instead of pulling the configured address that it pulled a dynamic address. I checked the Address Binding page and see that the dynamic entry that corresponds with the WAP321 has a Client Identifier rather than a MAC address. I changed the static entry for the WAP321 to use the client identifier displayed in the dynamic entry, and now the WAP321 pulls the configured static address. Is this expected behavior?
Thanks,
Bob

With the SX300/500 it is required the client identifier, it doesn't automatically insert it. If static DHCP is made on the switch and you didn't need client identifier, that is more or less fortunate behavior for you
So to answer this question, the expected behavior is to configure client identifier for static DHCP entry.
-Tom
Please mark answered for helpful posts
http://blogs.cisco.com/smallbusiness/

DHCP on SG300-10P for VLAN

Using an SG300-10P with firmware 1.3.7.18 and boot version 1.3.5.06 there's an option to run a DHCP server on the device. If this is really a full DHCP server, documentation is spotty, can I create a DHCP zone to serve VLAN 25 and only VLAN 25?

According to documentation it should be possible:
Switch functions as an IPv4 DHCP Server serving IP addresses for multiple DHCP pools/scopes
Rigth now I do not have access to one SSG but I will check it tomorrow when I work with one of my clients for the specific path,
Regards,
Jcarvaja

SG300 - DHCP implementation

Hello and thanks in advance for your help.
I set an SG300 switche in layer 3 mode with 3 vlans.
I need to give IPs to a whole vlan machines. Do the switch have a DHCP server per vlan? Can someine help me to configure this?
thanks!

Hi Angel,
As the datasheet says;
Dynamic Host Configuration Protocol (DHCP) Relay at Layer 2
Relay of DHCP traffic to DHCP server in different VLAN. Works with DHCP Option 82
The DHCP Address Allocation Using Option 82 feature provides the Dynamic Host Configuration Protocol (DHCP) server the ability to allocate dynamic IP addresses based on the relay information option (option 82) information sent by the relay agent.
Automatic DHCP address allocation is typically based on an IP address, whether it be the gateway address (giaddr field of the DHCP packet) or the incoming interface IP address. In some networks, it is necessary to use additional information to further determine which IP addresses to allocate. By using option 82, the relay agent has long been able to include additional information about itself when forwarding client-originated DHCP packets to a DHCP server. The DHCP Address Allocation Using Option 82 feature now allows the DHCP server to also use option 82 as a means to provide additional information to properly allocate IP addresses to DHCP clients.
In our case option 82 information includes which VLAN the DHCP request came from.
regards Dave

SG300 won't insert option82 during DHCP relay

Hey guys, anyone having trouble getting an SG300 series switch to insert option82 information? I have DHCP relay working successfully between two VLANs, however, I would like to identify where the client is connected in order to set their routing preferences optimally.
switch-20-0#show ip dhcp relay DHCP relay is EnabledOption 82 is EnabledMaximum number of supported VLANs without IP Address is 256Number of DHCP Relays enabled on VLANs without IP Address is 1DHCP relay is not configured on any port.DHCP relay is enabled on Vlans: 20Active: 20Inactive: Servers: 192.168.0.2
I have to missing something simple. Any help, or even "hey did you try" type answers very much appreciated!

http://www.cloudshark.org/captures/f1dbc2e0e9a6
I had already done this at some point, but I tried again this morning after a cup of coffee. At some point this started working!
Now I just need Dnsmasq to recognize this info!

Dhcp sg300 vlan

Okay. I have two scopes for two vlans configured on the sg300. When I put my laptop in vlan 1 I get an ip from 192.168.0.0/24. I then release the ip, I put the port my laptop is in into vlan 20 and try to renew to get an ip from 172.20.20.0/24 subnet associated with vlan 20 but I get an ip from 192.168.0.0/24 which is associated with vlan 1. The only way to get this to work is I have to go into the sg300 and delete the dhcp binding and then renew and I then get an IP address from 172.20.20.0. I would have thought that if I put the laptop in vlan 20 and released and renewed the sg300 would give me an IP address from 172.20.20.0 not 192.168.0.0 which is associated with vlan 1. What am I missing? Why is the sg300 responding with an ip from different vlan?
Sent from Cisco Technical Support iPad App

I've also experienced this and there was a similar post unanswered this month I believe. It may not be considered a bug or a problem since hosts aren't expected to change vlans like they do when we use are PCs for testing. Personally I would think that each vlan would have it's own isolated binding table as well as every other table, array or structures. Maybe some one can explain a solution or the reason why this is normal.

CSCuh07704 - SG300 - Hosts pull incorrect IP address from DHCP server

FYI. There will be a new release of software this month.

Dear Patrick,
Thank you for the feedback to the Small Business Support Community. You are right, the CSCuh07704 has already been given the "Resolved" status by 09-22-2013 and will be covered in the new firmware release, and just to give others a better idea of what the problem was:
B>Symptom:
Hosts will obtain incorrect IP address.
Conditions:
Issue occurs when the switch is in Layer 3 mode and embedded DHCP server is enabled.
Thank you again for your commitment and please do not hesitate to reach us back if there is anything we may assist you with in the meantime.
Kind regards,
Jeffrey Rodriguez S. .:|:.:|:.
Cisco Customer Support Engineer
*Please rate the Post so other will know when an answer has been found.

SG300 : erreurs de DHCP

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