Recently I have been playing around with the aircrack suite and in particular the aireplay-ng tool. This tool may be used for ARP replay attacks, however it requires that the monitor mode interface is able to switch channels to the channel of the target device / access point. For some reason my monitor interface was stuck in channel -1. So to fix this I found a forum post on Ubuntu Forums which solves this problem: [http://ubuntuforums.org/showpost.php?p=10550806&postcount=6](https://web.archive.org/web/20140529023833/http://ubuntuforums.org/showthread.php?t=1685960&s=04b60b381f6b7a33b76df6a8f04bb39f&p=10550806#post10550806)
You can apply this to the wlan interface to put it directly into monitor mode and avoid using the airmon-ng tool altogether if you wish. You may also be able to apply this to the mon0 interface created by the airmon-ng tool as well, however I have not tried it yet.
The bulk of the problem is just the order in which monitor mode and channel are enabled, it must follow the order as follows:
```
ifconfig $IFACE down
iwconfig $IFACE mode managed
ifconfig $IFACE up
iwconfig $IFACE channel $@
ifconfig $IFACE down
iwconfig $IFACE mode monitor
ifconfig $IFACE up
```
Hope this solves some problems…