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Comment by imajes | Hacker News Reader

8 ip addresses per attendee? That's a little high. It's incredibly hard to make DHCP work at that scale, and allocating 8 per attendee is wrong. Try 4 - if you're being nice - or 2 if you're constrained. (2 = one smartphone/tablet and a computer).

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one of the reasons to go high on IP addresses is because many devices don't release their leases properly, which can cause all sorts of havoc.

That's true. but having dhcp capacity for more than 255 IPs is hard (or, expensive). for a 20-30 person hackday, the organizer shouldn't be worrying about overkill network provision, and should spend that time/money worrying about good food, or something else. (imho)

for a 20-30 person hackday, it's not so much of a big problem. You wouldn't need more than a /24 for that, and you'd still be inside the * 8. But most tech events with more than 100-ish people I've been to have failed on their wifi at some point, and it's normally for this reason.

20/30 people on a regular router that has an IP range of 255 IPs will quite often fall over, I've seen it happen more than once.

right, I'm not so sure that's because of DHCP, though.

DHCP pool being exhausted or NAT table getting full are the two main problems I've seen at hackdays

Also, that's mostly when you don't tell people "hey, can you not put your iPhones and Android mobile phones on the wireless?"

The issue is mainly that domestic routers NAT tables tend to overflow with that many users on them.

Either this causes them to reboot (if they're crappy) or truncate the table, killing the oldest connection.

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