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I am setting up a Cisco 891-K9 with dual WAN. How do I setup policy based routing for all torrent traffic to be sent over the secondary WAN link?

I recall seeing routers that detect traffic type. Do they just look for traffic on common torrent ports (6881-6889)?

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  • Torrents are not relaying on these common ports only (6881 - 6889) now a day. A vast range of ports are being used for it. – engineerbaz Aug 4 '13 at 21:03
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    One major issue that you will find with the majority of torrent providers these days is that NBAR won't pick up the application as BT as the packets can be encrypted and using pretty much any port. – David Rothera Aug 4 '13 at 22:01
  • So NBAR seems like a good idea since I'm not trying to block P2P, just route it. @DavidRothera - when you write that BT packets can be encrypted, is that a standard or just users trying to evade detection and blocking? – SAR622 Aug 5 '13 at 10:59
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    Yes to both. The standard was drafted to evade ISP's extreme throttling, or complete blockade, of anything looking like bittorrent traffic. – Ricky Aug 5 '13 at 21:22
  • Did any answer help you? if so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer. – Ron Maupin Aug 8 '17 at 14:10
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Assuming you can choose the port range your torrent client will use, you should set up PBR as follow:

ip access-list extended torrent
 permit tcp any range $STARTPORT $ENDPORT any
!
interface $LAN
 ip policy route-map PBR  
!
route-map PBR permit 10
 match ip address torrent
 set ip next-hop $WAN1-IP       
!
route-map Texas permit 20
 set ip next-hop $WAN2-IP       
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  • And ensure your client is set to advertise a WAN1 IP, otherwise, as you aren't controlling client-tracker communications (looks like normal http traffic, sometimes on port 80), it could see you as WAN2. – Ricky Aug 5 '13 at 21:24
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    Also, include UDP. (utorrent and DHT use udp, too) – Ricky Aug 5 '13 at 21:28

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