Hotspot already logged in via and status is Active but just stuck at login page and can't go Internet

RouterOS General
1

Hi All,

This is a very rare situation but we encountered few times in a year as we are a hotel with > 1000 wifi users. This may be a bug at the Hotspot 1-1 NAT.

  1. Host was allocated an IP from DHCP e.g 10.10.100.1
  2. Host was presented Hotspot login page
  3. Host logged in with correct hotspot username + password.
  4. Host entry was found under Hotspot Hosts tab, Host Mac Address XXXX, Address = 10.10.100.1, To Address = 10.10.211.10, Status is A (Active)
  5. Host entry was found under Hotspot Active tab, Host Mac Address XXXX, Address = 10.10.211.10, uptime = …

Up until here all Mikrotik Hotspot mechanism seems to be ok. BUT Host device stuck on the login page and could not go Internet.
WHY ?

  1. We looked at the ARP on Mikrotik and 10.10.211.10 is mapped to another Mac Address YYYY, not the intended Host Mac Address XXXX.
    (In working scenario, ARP entries will be Mac Address XXXX, 10.10.100.1, Mac Address XXXX, 10.10.211.10)
    (this issue scenario, ARP entries Mac Address XXXX, 10.10.100.1, Mac Address YYYY, 10.10.211.10)

Hence this caused the issue that packets were not forwarding to the host and it stuck at login page.

The question is why it behaved in this way ? Was it a bug at the translation table or network timing issue ?

Again this is very rare considering we only encountered few times per year and everyday there are > 1000 users.

Appreciate if someone could help to enlighten the above.

Thank you very much.

Regards,
Josh

2

Hey Josh, this has happened with me as well before.
Majority of times it was a faulty NIC card which was taking up multiple IP through DHCP or rarely a user who manually entered IP address
I am not sure if it is system fault anyhow, you can enable certain parameters in DHCP (authoritative)

3

I have seen lots of explanations of why, most are centered around temporary network issues or bad client devices/drivers. The best solution is to disable the 1:1 NAT by setting the dhcp-pool=none. The 1:1 NAT was introduced to allow devices that had a static IP Address configured to be able to connect to the hotspot. That practice of setting static addresses is no so common anymore if not completely extinct.