Extremely slow DHCP leases

[JHanko]

A few months ago, I decided to replace my aging Unifi system and stumbled upon home labs and open source firewalls. I never heard of either before this. This got me curious and I fell down the rabbit hole. Since then, I have learned a lot about networking and have put together a system including a pFsense firewall, TrueNAS storage, Aruba S2500 switch, Aruba AP-515 access point and an APC UPS connected with ethernet. Everything works perfect, except for one thing... All wired ethernet clients have a 30-45 second delay getting an IP address and internet connection. Once connected, it is perfectly fine. Fast and stable. At first I thought this may have been a pfSense thing, but now I don't think it is. Clients connecting to WIFI get an IP address and internet connection within 5 seconds, so I think the problem is in my switch configuration. I don't have the experience to find the issue (or fix it).

My system is as follows:
PfSense running on Supermicro S12SDV > 10gb trunk line > Aruba S2500 switch. DHCP servers, VLANs and switching all done with pFsense.
The switch is connected to an Aruba AP-515 access point via 2 link aggregated trunk lines. This is all working perfectly.
I have switch ports assigned to different VLANs and this is where I think I the problem may be. The ports are working correctly as far as assigning the correct VLAN address to the client, but it's extremely slow. First of all, I have absolutely no experience with command line configuration, so everything I did with the switch was done through the web interface. I could not figure out how to assign a port to a VLAN unless I created a VLAN in the switch. I created duplicated VLANs in the switch to match the VLANs in pFsense. I was then able to assign ports. Is it possible that the duplicate VLANs are what is causing the 30-45 second delay? If so, how can I assign ports to a VLAN, if it's not in the switch? Again, once a wired client gets an IP address and internet connection, everything is fine. This delay is getting annoying though. I would appreciate any suggestions.

 

[nexox]

There are a couple potential issues that could cause this sort of thing - my two initial ideas are either you've accidentally got another DHCP server running somewhere (maybe the switch,) or something is up with the phase of DHCP where a client attempts to use ARP to resolve the new address the server offered to avoid conflicts with an existing device on that address. Further debugging would require either detailed output from a dhcp client, with timestamps (or you can just watch it an indicate where a long pause occurs,) or a packet capture from the client and/or DHCP server on UDP port 67 or 68.

 

[klui]

Your problem is caused by spanning tree discovery. Either disable STP or its variants or add portfast to the stp profile.

 

[JHanko]

There are a couple potential issues that could cause this sort of thing

I'm 100% confident that there are no hidden DHCP servers running anywhere. You lost me on the rest though...

 

[JHanko]

Your problem is caused by spanning tree discovery. Either disable STP or its variants or add portfast to the stp profile.

Thanks for the suggestion. Hopefully it's something this simple. I have no idea where to disable it though. In pFsense or the switch. I'm poking around now. So, creating duplicate VLANs in the switch was the correct way to assign ports then?

 

[cesmith9999]

STP is a switch feature.


Chris

 

[JHanko]

Well, I've gone through every single configuration page and cannot fine anything related to STP.

 

[klui]

Download the ArubaOS 7.4 User Guide and search for "spanning tree." That gives you an introduction on how to determine which mode is active. Then search for "portfast."

 

[JHanko]

I already have that guide and looked through it. It is all related to command line interface, which is way above my head...

 

[JHanko]

The other thing that confuses me is that I have read that STP is disabled by default on all Aruba switches. This switch was factory reset and I certainly didn't enable it.

 

[JHanko]

OK, so I figured out how to enable portfast through the command terminal, but I am doing one port at a time. I need to enable it on ports 0/0/0 - 0/0/45. Is there any way to enable all of these ports at once? If not, I'll be here all night.

 

[pricklypunter]

Back to reading the manual...look for how to enter a port range in commands

I believe this is supported from ver 10.3 onwards...

 

[JHanko]

I learned how to disable the spanning tree altogether. Wired DHCP leases are instantaneous now. Thank you all for the help!

 

[klui]

Great. I'm glad you got it working. It takes a different thought process but CLI is nothing to be feared.

For your reference in the user guide:

Spanning Tree Modes​

The spanning tree mode is set to MSTP in factory default.​

Because MSTP is enabled by default all you need to do is to change "default" mstp-profile and it will be applied to all ports. No need to assign the profile to each port.

Use

(ArubaS2500-48P-US) (config) #interface range gigabitethernet 0/0/0-0/0/45
(ArubaS2500-48P-US) (config-range) #