Linux Solutions

Welcome to the tutorial guide. The guide will provide a user with advise and guidance on filtering.
If a user has a PRIO qdisc called ‘10:’ which contains three classes, and he/she wants to assign all traffic from and to port 22 to the highest priority band, the filters would be:
# tc filter add dev eth0 protocol ip parent 10: prio 1 u32 match \
ip dport 22 0xffff flowid 10:1
# tc filter add dev eth0 protocol ip parent 10: prio 1 u32 match \
ip sport 80 0xffff flowid 10:1
# tc filter add dev eth0 protocol ip parent 10: prio 2 flowid 10:2
Let’s see what does this mean. It means that: attach to eth0, node 10: a priority 1 u32 filter that matches on IP destination port 22 *exactly* and send it to band 10:1. And it then repeats the same for source port 80. The last command says that anything unmatched so far should go to band 10:2, the next-highest priority.
A user needs to add ‘eth0′, or whatever his/her interface is called, because each interface has a unique namespace of handles.
If a user wants to select on an IP address, thene he/she needs to use this:
# tc filter add dev eth0 parent 10:0 protocol ip prio 1 u32 \
match ip dst 4.3.2.1/32 flowid 10:1
# tc filter add dev eth0 parent 10:0 protocol ip prio 1 u32 \
match ip src 1.2.3.4/32 flowid 10:1
# tc filter add dev eth0 protocol ip parent 10: prio 2 \
flowid 10:2
This assigns traffic to 4.3.2.1 and traffic from 1.2.3.4 to the highest priority queue, and the rest to the next-highest one.
A user can concatenate matches, to match on traffic from 1.2.3.4 and from port 80, do this:
# tc filter add dev eth0 parent 10:0 protocol ip prio 1 u32 match ip src 4.3.2.1/32 \
match ip sport 80 0xffff flowid 10:1.

If a user followed advise and guidance as provided in this tutorial guide then he/she learnt about filtering.