You dont want to buffer them. Please read some background theory on TCP
before you conclude that. You might want to throw some frames away.
> SMTP packets (port 25) to be delt with in a higher priority over HTTP (80)
> packets. Priorities have to be dynamic enough to accomodate network
> traffic according to workload on each incoming/outgoing port.
IPv4 has a type of service field (TOS) that Linux honours. Make your hosts
use it right and queueing will favour the higher priorities. The firewall
code can rewrite the TOS fields of boxes that dont set their TOS right or
to your liking