Hi
I believe I found an abnormal behavior in my Mikrotik. The support page in mikrotik.com seems to be interested only in vulnerabilities (not the case!) and kind of makes an effort to deter you from disturbing Mikrotik developers. Anyway, it's still an abnormal behavior and I believe someone up there should be notified. Where do I publish (if I should?) such things?
I believe I'm taking the most innocent action by asking this naive question in the Beginners Basics forum....

thanks!

If you're sure it's bug, support shouldn't be offended by it. It will probably be nice change from all those "I don't know what I'm doing, but I'm sure your software is broken!" they are probably getting tons of. If you're less sure, you can always post it here and someone else can confirm or disprove it.

Ok. Fair enough.

So, a hap AC with Long Term 6.44.5 and a Macbook OS Mojave walk into a bar....
The hap AC has blank configuration. The Mac is connected to the hap switch. On the quick Set page I put an ip address (xxx.xxx.xxx.1) on the local network. A netmask (255.255.255.192/27) and a dhcp range (xxx.xxx.xxx.10-xxx.xxx.xxx.31). That's all. I try to connect the Macbook to any of the 2 wireless networks so I can keep configuring ROS and be able to use the ethernet cable to connect to the ISP router. I can't connect to the wireless network. It takes a long time, and then it says it can't establish a connection. After many tests I isolate the problem: If I change the netmask to 255.255.255.0/24 I easily connect to the wifi. If I change it back to /27 I can't connect to the wifi. In the end I went with /26 and it's working fine.

So the Barman says to the Hap AC, "hey, your IP address should have the CIDR notation, not your subnet mask"

Something else, DHCP scope should not include X.x.x.31, that is the broadcast address for /27, and routeros typically assigns IPs from high to low, so maybe you were issued .31 IP

How about all that text before the vulnerability section?
https://mikrotik.com/support

@normis: IMHO it could use some improvements. Let's say I found a bug in RouterOS, but not a vulnerability. It's for real, I know it's bug and not my mistake, something is clearly misbehaving in RouterOS, even in latest beta. Now what? I didn't buy RouterBoard directly from MikroTik, like >99% of users. There's no point hiring consultants, because they can't fix it, and the same goes for this forum. Based on the text on support page, I really don't know if I should bother support or not, it almost sounds like I shouldn't. But how would you learn about the broken stuff then, you do want to fix bugs, right?

It clearly says to contact the seller, or email support@mikrotik.com with detailed steps on what to send.

Most people think they found a bug, when it's actually some basic mistake on their part. Value added distributors do provide support, just make sure you buy from such a distributor, not from some anonymous webpage or ebay: https://mikrotik.com/buy

So the Barman says to the Hap AC, "hey, your IP address should have the CIDR notation, not your subnet mask"

Something else, DHCP scope should not include X.x.x.31, that is the broadcast address for /27, and routeros typically assigns IPs from high to low, so maybe you were issued .31 IP

Yep, I though about that this morning when I was walking the dogs. I recalled that the macbook wifi always gets the last ip from a dhcp-pool (not true for the ethernet port, just the wifi). I'm sure it was trying to assign the 31. My routeros devices always assign ip's to every machine starting from the first available. The only exception is the mac's wifi.

thanks

There is no defined order for assignment of the addresses in a pool. It often starts from lowest but under some conditions it may assign higher addresses.
And certainly when a device has had an address before, it will often ask "can I have this address again?" and they router will allow it when it is a free address in the pool.
So when that address was valid in another network, it may get that (now invalid) address on your network.
In any case, don't put invalid addresses in your pool range, they are not checked at all.

It clearly says to contact the seller, or email support@mikrotik.com with detailed steps on what to send.

I'm not sure, to me the second part of https://mikrotik.com/support looks as follow-up to first one, i.e. if I bought directly from you in last 30 days, then I have right to ask your support (and following section lists what exactly I should do), otherwise I shouldn't bother you and ask distributor/seller instead. It made me feel guilty every time I wrote to you (but it was only five times total and I have relatively good score with four bugs and only one misundertanding about unexpected feature). And official distributors, it wouldn't really occur to me to contact them, the ones here look like any other random computer eshop, with stuff from many other manufacturers, etc. Maybe if I was buying devices by thousands and had closer ties with them, I would sometimes ask them to help me with something I don't know, but even then it would seem pointless to discuss bugs with them, when they can't fix them anyway.

There is no defined order for assignment of the addresses in a pool. It often starts from lowest but under some conditions it may assign higher addresses.
And certainly when a device has had an address before, it will often ask "can I have this address again?" and they router will allow it when it is a free address in the pool.
So when that address was valid in another network, it may get that (now invalid) address on your network.
In any case, don't put invalid addresses in your pool range, they are not checked at all.

Yep, my misunderstanding is fully understood.
Anyway, I have about 25 different devices with ip addresses. Without exception, the ip's are distributed starting from the first ip available. But iOS wifi devices always start form the last. Right now I have a iphone on 61 and the macbook on 60 in a /26 network. So, with limited statistics, I would say iOS devices always ask for the highest ip available.

No that is not correct, it depends on the size of the subnet as well.
I run several WiFi networks with /22 networks on MikroTik routers and normally the addresses are assigned from lowest up, also for Apple devices.
But on smaller networks it tends to be from top down.
There is no defined or preferred behavior for a DHCP server, e.g. the ISC DHCP server also started to use this down-from-top assignment some years ago, lots of users complained, the maintainers refused to do something about it because they considered it irrelevant, but a year or two later it was changed anyway, back to the upward assignment.
Anyway, when you do not like an address you can use "make static", then change the address to what you want, and reconnect the client device.

In other words, its working as designed and we want an enhancement ( to better control dhcp behaviour)?