# Can we use ALTQ and PF to modify packets which acts as a bridge in testing envronmnt?



## nikeadasa (Sep 22, 2013)

Can we use ALTQ with PF to modify packets in freebsd FreeBSD which acts as bridge in my testing environment? If yes *I* want to know the PF rule to modify packets.

Right now *I* am using DUMMYNET with IPFW as traffic shapers. It*'*s working but it does not have the functionality of modifying packets. Which is the preferred traffic shaping tool of freebsd FreeBSD? I am expecting the following functionality for my traffic shaper.

1. Dropping of packets
2. Keep log of dropped packets
3. Modify packets if possible


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## gnoma (Sep 22, 2013)

Hello,

Have you tryed adding the following lines to file file /usr/src/sys/`uname -p`/conf/PFKERNEL:


```
options         ALTQ
options         ALTQ_CBQ
options         ALTQ_RED
options         ALTQ_RIO
options         ALTQ_HFSC
options         ALTQ_PRIQ
options         ALTQ_NOPCC
```

And then recompile kernel?


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## nikeadasa (Sep 23, 2013)

Hello @gnoma,

I have not tried it yet. I want to know if it's possible to modify packet or not? Because I have gone through the FreeBSD.org site so many times. Initially they have mentioned that PF and ALTQ can be used to modify, drop or pass packets in the section 30.4.4 http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/firewalls-pf.html. Actually I wanted the functionality of modifying packets, is that possible?


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