pf ALTQ bandwidth limited to a 32bit value (4294Mb)

Peter N. M. Hansteen peter at
Wed Jul 6 16:50:22 UTC 2011

Calomel Org <infallibilismindefeasibility at> writes:

> ALTQ using hfsc is limited to a maximum parent bandwidth of 4294Mb.
> This value is 2^32 or 4,294,967,296 bits. If you set the bandwidth any
> higher, altq will flip back to zero. This "bug" was found when trying
> to test 10 gigabit and 40 gigabit bandwidth models. These tests were
> done on OpenBSD 32bit and 64bit as well as FreeBSD 32bit and 64bit.

Nice to hear you've got access to relatively high end gear for testing,
I'm sure it will come in handy when the time comes to test any proposed

The obvious workaround in the short term is to do the traffic shaping
and filtering a bit closer to the end user, where bandwidth is a bit
more scarce.  In the slightly longer term, I'm sure a verified bug
report (with patches against -current code if feasible) would be much

- Peter

Peter N. M. Hansteen, member of the first RFC 1149 implementation team
"Remember to set the evil bit on all malicious network traffic"
delilah spamd[29949]: disconnected after 42673 seconds.

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