Hi everyone, I'm using hAP AC2 as my main router, everything working fine, except 1 problem.
Many of my users complained about the connection time, the situation is like below:

1.) 1st time connect to my network, got their IP from DHCP server and start browsing after few seconds, everything fine.
2.) Once they leave the building for lunch, come back and get connect, got their IP from DHCP, now they have to wait about 30 seconds before they can start browsing. It can't even reach the router from winbox, the connection was refused, there is nothing we can do except wait for it, checked IP was ok, got it from DHCP server within 2 seconds, but can't use it at all. Happens on LAN and Wireless, and log said "dhcp1 assigned 192.168.0.x to xx:xx:xx:xx:xx:xx", nothing special.

I did a minimized setup for my router (Setup PPPoE, put the PPPoE in WAN list, DHCP server, IP Address, DNS, password, the rest left default), still same problem occurs.

Does anyone experience it before?

Hey. What is your lease time on dhcp server?

Hey. What is your lease time on dhcp server?

04:00:00, 4 hours

Hey. What is your lease time on dhcp server?

04:00:00, 4 hours

Change it to 1 hour and observe for a day. Not good? Change it for 10 minutes.

How much clients do you have on this router and what subnet range do you have on dhcp server? Perhaps your server suffering from address space starvation. Feed it

Hey. What is your lease time on dhcp server?

04:00:00, 4 hours

Change it to 1 hour and observe for a day. Not good? Change it for 10 minutes.

How much clients do you have on this router and what subnet range do you have on dhcp server? Perhaps your server suffering from address space starvation. Feed it

It’s just about 20+ clients, only 1 simple network (192.168.0.0/24, 255.255.255.0) nothing fancy, we change to MikroTik due to its good reputation of stability, but now even worst, I believe it’s just some minor error but I just can’t seems to figure it out Really need some helps

Oh ya, forgot to mention this happened on both dynamic and static client

Oh ya, forgot to mention this happened on both dynamic and static client

Try to test your wired connection. Then wireless.

Oh ya, forgot to mention this happened on both dynamic and static client

Try to test your wired connection. Then wireless.

Hi, both are same, sometimes gonna wait and sometimes don’t have to wait, really weird

30 second delay is usually a bad DNS entry. Test your name servers. One is probably not responding.

Another possibility, turn off hardware offload for the LAN ports which are in a bridge.

I've seen one network where the packets were simply disappearing for random amounts of time, until I turned off the hardware offload feature. That was not as regular as a thirty second timeout. The network was somewhat complicated. There were wireless bridge devices linking bridged hAP AC-lite units in different buildings. I did not isolate down to the specific conditions which cause the problem. I've not seen the problem happen elsewhere, yet.

30 second delay is usually a bad DNS entry. Test your name servers. One is probably not responding.

I'm using 1.1.1.1/1.0.0.1 as my DNS which is reliable in my ISP connection, never have a ping lost, all my clients will get 192.168.0.1/1.1.1.1/1.0.0.1 as DNS server.
Really weird, 1st time connection just have to wait few seconds to get connection AFTER they got the DHCP assigned IP address, but if I disconnect and reconnect then have to wait 30~60seconds, like a penalty.
Switch back to my Netgear R7800 and everything back to normal, get connection immediately after DHCP assigned IP address, why MikroTik? Why?

Wait, I seems found the source of the problem, it was my Synology NAS. I wanna do a troubleshooting by remove them all and add them 1 by 1, once my NAS plugged in the problem will occur, once I unplug it everything back to normal immediately, really weird. Will monitor it few days to see if the problem occurs again, thanks u guys for trying to help me up, really thanks!

Ah, the joys of failing or misconfigured network hardware.... Failing network interfaces can do weird things to the network.

I don't have a synology. Does it have any routing / proxy arp options?

Found the problem, it was the "Store leases on disk" problem, not Unifi controller. Test after test, reset after reset, I can confirm it causes the problem, changed it to "never" fully solved the problem.

Some configuration in the unify controller was causing the problem then...

Some configuration in the unify controller was causing the problem then...

Could be, it was normal when I was using normal Windows version, but soon after I switched it to Windows service mode it started to crazy, lazy to dig out why since I’m now put those Unifi aside and test hAP AC2 + cAP AC with 6.46b59 CAPsMAN, it does improved wireless performance from 370mbps to now 390mbps, and much stable, MikroTik really improving the wireless performance, thumbs up!

I’m now put those Unifi aside and test hAP AC2 + cAP AC with 6.46b59 CAPsMAN

Great...