18 Posts

June 19th, 2014 12:00

The 6248 has no default gateway. It will not let me put 192.168.1.1 because it does not reside in the same subnet as the 6248 (192.168.99.1)

The 2708 has 192.168.1.1 listed as its default gateway.

At this point, the network has too many complexities for me to untangle. I'm very glad that at the least I have DHCP resolved for when we finally migrate our server to the new location.

Once the server is in place, and the gateway/firewall are plugged directly into the 6248; I will revisit the proper configuration of this network.

Some tips to anyone who might have a similar issue: Check your management VLAN. It cannot be the same as VLAN 1 if you expect routing to work from VLAN 1 to anywhere else because the management VLAN cannot be routed. Also check static routing from your gateway, make sure the gateway has a return to the ips of your VLANS ie: 192.168.2.0 255.255.255.0 gateway_ip

Thats all for now. Thank you everyone who has contributed

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9.5K Posts

June 12th, 2014 15:00

Hi jhartsou,

Since you have ip routing enabled you don’t need dhcp l2relay. It is for layer 2 only. Page 461 ftp://ftp.dell.com/Manuals/all-products/esuprt_ser_stor_net/esuprt_networking/esuprt_net_fxd_prt_swtchs/powerconnect-6224_User%27s%20Guide_en-us.pdf

 

You should be able to use the ip helper-address command pointing to the DHCP server.

Ip helper-address 192.168.2.x dhcp

With x being the IP address of the DHCP server.

Page 712 ftp://ftp.dell.com/Manuals/all-products/esuprt_ser_stor_net/esuprt_powerconnect/powerconnect-6248_Reference%20Guide_en-us.pdf

 

 

What does the command return? show ip helper-a

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9.5K Posts

June 13th, 2014 08:00

That looks fine, port 2 can pass all of the VLANs.

18 Posts

June 13th, 2014 08:00

I reconfigured everything to use only ip helper, and removed dhcp l2relay

IP Helper configuration:

UDP Destination Port     Server Address      IsDiscard      Hit Count

67                                       192.168.1.150        False              9

IP Helper statistics:

DHCP Client Messages Received 9

DHCP Client Messages Relayed 9

DHCP Server Messages Received 0

DHCP Server Messages Relayed 0

UDP Client Messages Received 9

UDP Client Messages Relayed 9

DHCP Client Messages Hop Count Exceeded Max 0

DHCP Pkts Rcvd Too Early 0

Received DHCP Client Messages With Giaddr As Local Address 0

UDP Pkts With Expired TTL 0

UDP Pkts Discarded 0

Something is being pointed to the DHCP server, but again no IPs are being assigned from the new pools. Is there anything else I should check for?

Thank you,

18 Posts

June 13th, 2014 08:00

2708 vlan membership: ports:

VLAN ID 1------------------------------

1 2 3 4 5 6 7 8

U U U U U U U U

VLAN ID 20----------------------------

1 2 3 4 5 6 7 8

T T

VLAN ID 30----------------------------

1 2 3 4 5 6 7 8

T T

Port 2 connects the point to point to the 6248P

Port 6 connection to DHCP server

Thank you for the tips Josh. Should the above config pass the traffic?

18 Posts

June 13th, 2014 08:00

OK. I'll reset the running config and get rid of l2relay. I thought since the powerconnect 2708 is only layer 2, that might have been the reason it won't work. In the meantime:

console#show ip helper-a

IP helper is enabled

Interface               UDP Port    Discard  Hit Count     Server Address

-------------------- ----------- ---------- ---------- ------------------

vlan 20                  Default         No        738      192.168.1.150

vlan 30                  Default         No          0      192.168.1.150

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9.5K Posts

June 13th, 2014 08:00

The 2708 shouldn’t be causing any issues, it should just pass traffic right through as long as the ports are set to handle the needed VLANs.

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9.5K Posts

June 13th, 2014 10:00

If the client has a static IP can it ping the DHCP server? Can the server ping the VLAN ip addresses? It looks like the helper is receiving and relaying packets from the client but isn’t getting anything from the server. I had the configuration double checked to make sure we were not missing anything and it is set correctly on the 6224. What does the DHCP server configuration look like? Are the clients on VLAN 20 and 30 pointing to the VLAN IP as their default gateway?

18 Posts

June 13th, 2014 13:00

Q: If the client has a static IP can it ping the DHCP server?

A: Assigned 192.168.2.2 to a PC plugged into VLAN 20. Pinging the DHCP server results in a "request timed out."

Q: Can the server ping the VLAN ip addresses?

A: Server cannot ping 192.168.2.1 or 192.168.2.2

Q: What does the DHCP server configuration look like?

A: Three scopes are active. 192.168.1.0 (Corp), 192.168.2.0 (PUBLIC), and 192.168.3.0 (VOIP). PUBLIC has a range of 192.168.2.1-254. Options are 003 Router (192.168.1.1), 006 DNS Servers (192.168.1.150), and 015 DNS Domain Name (corp.local)

Q: Are the clients on VLAN 20 and 30 pointing to the VLAN IP as their default gateway?

A: I statically changed the gateway of the PC connected to VLAN 20 to 192.168.2.1. Still cannot ping DHCP. Is this what you are asking?

18 Posts

June 13th, 2014 14:00

VLAN 20 should not be able to communicate with VLAN 1 or VLAN 30 anyway right? We added "Ip helper-address 192.168.1.150 dhcp" to VLANs 20 and 30. Only DHCP requests should be passed?

VLAN 20 should only have internet access. No access to the file server or other VLAN 1 traffic. We can achieve this even with routing enabled, right?

6248p is updated: 3.3.10.3

2708 is surprisingly updated too: 1.0.1.05

VLAN 20 and 30 are tagged on both the point to point connection and the DHCP connection (port 2 and 6) on the 2708.

Thank you so much for your suggestions so far. I hope we are able to help someone else with this same issue too.

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9.5K Posts

June 13th, 2014 14:00

On the configuration that you posted earlier, ip routing was enabled, which would allow all VLANs to communicate with each other, the 6224 would route between the VLANs. To block the traffic you would ACLs to deny traffic from VLAN 20 to VLAN 1. The statically set PC should be able to ping 192.168.3.1

Ip helper address is just for forwarding the bootp packets to the DHCP server on a different subnet. Since the client request for an ip address is a broadcast it would normally be dropped and not routed.

A ping since it is a unicast packet should be routed with ip routing enabled.

When you have a client come on the network on VLAN 20 it broadcasts a request for DHCP, the switch is receiving it, your statistics showed that, and then the switch should forward that request 192.168.1.150 with the switch’s information, get the reply from the server and send it back to the client. However the part where it goes from the switch to the server is where the process is breaking.

Interface 1/g11 is going to the 2708 from the 6224 right?

What does show?

show ip route

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9.5K Posts

June 13th, 2014 14:00

Thanks, it seems like it is not routing to VLAN 1, if it was routing and the problem was with ip helper it would be able to ping with a static address. Is the firmware up to date?

6200 series firmware: http://www.dell.com/support/home/us/en/04/Drivers/DriversDetails?driverId=Y7YJ9&fileId=3354403342&osCode=NAA&productCode=powerconnect-6224&languageCode=EN&categoryId=NI

 

2708: http://www.dell.com/support/home/us/en/04/Drivers/DriversDetails?driverId=R112896&fileId=2731111725&osCode=NAA&productCode=powerconnect-2708&languageCode=EN&categoryId=NI

 

You may also want to try adding tagged VLAN 20 and 30 to port 6 on the 2708 and see if that helps.

18 Posts

June 13th, 2014 15:00

I tried connecting the point to point to our DHCP server to see if the issue would be resolved. In theory this would be like connecting the 6248 directly to our server.

The PC on VLAN 20 still could not communicate with DHCP.

At this point I can remove the 2708 as an issue, since it still will not function even without it. Something must be wrong with the 6248's configuration.

Will continue with other options Monday morning.

thank you everyone. Have a great weekend.

18 Posts

June 16th, 2014 10:00

Here is my running-config. Why are vlans not routing to the DHCP server?

console#show running-config

!Current Configuration:

!System Description "PowerConnect 6248P, 3.3.10.3, VxWorks 6.5"

!System Software Version 3.3.10.3

!Cut-through mode is configured as disabled

!

configure

vlan database

vlan 20,30

vlan routing 20 1

vlan routing 30 2

exit

stack

member 1 5

exit

ip address 192.168.1.180 255.255.255.0

ip default-gateway 192.168.1.1

ip routing

interface vlan 20

name "PUBLIC"

routing

ip address 192.168.2.1 255.255.255.0

ip helper-address 192.168.1.150 dhcp

exit

interface vlan 30

name "VOIP"

routing

ip address 192.168.3.1 255.255.255.0

ip helper-address 192.168.1.150 dhcp

exit

!

interface ethernet 1/g1

switchport mode general

switchport general pvid 20

switchport general allowed vlan add 20

switchport general allowed vlan remove 1

exit

!

interface ethernet 1/g2

switchport mode general

switchport general pvid 20

switchport general allowed vlan add 20

switchport general allowed vlan remove 1

exit

!

interface ethernet 1/g3

switchport mode general

switchport general pvid 30

switchport general allowed vlan add 30

switchport general allowed vlan remove 1

exit

!

interface ethernet 1/g4

switchport mode general

switchport general pvid 30

switchport general allowed vlan add 30

switchport general allowed vlan remove 1

exit

!

interface ethernet 1/g5

switchport mode general

switchport general pvid 30

switchport general allowed vlan add 30

switchport general allowed vlan remove 1

exit

!

interface ethernet 1/g6

switchport mode general

switchport general pvid 30

switchport general allowed vlan add 30

switchport general allowed vlan remove 1

exit

!

interface ethernet 1/g11

switchport mode general

switchport general allowed vlan add 20,30 tagged

exit

18 Posts

June 16th, 2014 13:00

Daniel,

I tried your experiment and:

gave 192.168.2.2 to PC #1 in VLAN 20

gave 192.168.3.2 to PC#2 in VLAN 30

pc 2 cannot ping pc 3. Neither can ping anything from VLAN 1

Obviously I am missing something fundamental here. In the end, all I need to to have

192.168.1.x (local company network traffic)

192.168.2.x (public accessible wifi)

192.168.3.x (voip traffic)

I want all three to remain separate. The only thing accessible to any of them should be the DHCP to dish out IPs. Am I going about this completely wrong?

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