February 17, 201214 yr Hi all, I've installed Transmission on my UnRAID server and it is nearly killing internet access at home. Internet access on the unRAID box is impossible (a simple ping to google results in 4-6 seconds latency). I have an Edimax BR6504N connected directly to the modem, and a Cisco-Linksys E4200 connected by Cat5 to the Edimax router. I tried reducing the maximum number of peers, limiting download and upload speed, disabled PEX, DHT, LPD and uTP to no avail. Am I missing something here?
February 17, 201214 yr I had an issue with cisco/linksys firmware on my old WRT54g where torrent activity would stop it from working. Might want to look into that. And see about installing DDWRT on that router.
February 17, 201214 yr May or may not be related to what you're experiencing but below are my notes I kept on the problems I ad with running transmission on unraid and a SMC2804WRBP-G router. Short version is I disabled SPI and Anti-DoS firewall protection based on the below referenced research which seems to have solved the problem. 10-05-11 was still seeing IE connection fails, 'syn flood' messages on SMC2804WRBP-G router web interface (security log), changed transmission config peer-limit-global from 55 to 35 peer-limit-per-torrent from 60 to 35 actual problem may be smc router setting (firewall,intrusion detection,SPI and Anti-DoS firewall protection)? disabled this, see below thread returned below settings peer-limit-global - 100 peer-limit-per-torrent - 60 https://forum.transmissionbt.com/viewtopic.php?f=4&t=5726 ... Had same problem with SYN FLOOD on my Belkin modem/router. Stopped the problem by turning off DoS checking. ,,, I want to verify that this solution works! I have a NETGEAR Router, switching off the SPI Firewall in the Router solved all the problems! ... For me, the problem is the firewall in my broadband router. Whenever Transmission is running the firewall is detecting SYN floods from my LAN (from my Mac that is), thus dropping these connection requests / packets. When i shut down Transmission, no more SYN floods are detected, and my network works again. I have solved this temporarily by disabling SYN flood detection in the router firewall. With that option disabled, the Internet works again. Apparently Transmission produces network traffic that makes all other connection requests made from other apps seems like SYN floods? I do not know how Transmission is implemented, but this seems really strange. This is easily tested by you guys out there with several computers on your LAN. If you can access the other machines or your network while running Transmission, but not the Internet, it is your router dropping your outgoing packets. ... It is the numerous connection requests from Transmission that is interpreted as a SYN flood of course. When testing i used only 2 torrents, with few peers per torrent (around 10), (settings: max global 100, max new conn 50) I find it strange that these few connections should cause the firewall to block packets. Another thing is that I get decent speeds with the firewall enabled. The firewall is blocking outgoing connections, how is this possible? But I guess it is from incoming connections (since the router is still letting these pass through) to the forwarded port. Thinking about the SYN flood filter in my firewall, I think it is safe to turn off. Since my bandwidth is about 20MBit I guess if someone tries to DoS my router with a SYN flood, the bandwidth will be filled either way? And I guess my ISP has similar (more expensive) filters in their system. 03-19-11 was still seeing IE connection fails, 'syn flood' messages on SMC2804WRBP-G router web interface (security log), changed transmission config peer-limit-global from 100 to 55
February 17, 201214 yr Author I had an issue with cisco/linksys firmware on my old WRT54g where torrent activity would stop it from working. Might want to look into that. And see about installing DDWRT on that router. I disabled NAT and firewall services on the Linksys router, since I already have NAT enabled on the Edimax router, so I do not think that the Linksys router is crippling the internet. I don't know how 200 connections (maximum number of peers) are disabling internet access.
February 17, 201214 yr Author May or may not be related to what you're experiencing but below are my notes I kept on the problems I ad with running transmission on unraid and a SMC2804WRBP-G router. Short version is I disabled SPI and Anti-DoS firewall protection based on the below referenced research which seems to have solved the problem. 10-05-11 was still seeing IE connection fails, 'syn flood' messages on SMC2804WRBP-G router web interface (security log), changed transmission config peer-limit-global from 55 to 35 peer-limit-per-torrent from 60 to 35 actual problem may be smc router setting (firewall,intrusion detection,SPI and Anti-DoS firewall protection)? disabled this, see below thread returned below settings peer-limit-global - 100 peer-limit-per-torrent - 60 https://forum.transmissionbt.com/viewtopic.php?f=4&t=5726 ... Had same problem with SYN FLOOD on my Belkin modem/router. Stopped the problem by turning off DoS checking. ,,, I want to verify that this solution works! I have a NETGEAR Router, switching off the SPI Firewall in the Router solved all the problems! ... For me, the problem is the firewall in my broadband router. Whenever Transmission is running the firewall is detecting SYN floods from my LAN (from my Mac that is), thus dropping these connection requests / packets. When i shut down Transmission, no more SYN floods are detected, and my network works again. I have solved this temporarily by disabling SYN flood detection in the router firewall. With that option disabled, the Internet works again. Apparently Transmission produces network traffic that makes all other connection requests made from other apps seems like SYN floods? I do not know how Transmission is implemented, but this seems really strange. This is easily tested by you guys out there with several computers on your LAN. If you can access the other machines or your network while running Transmission, but not the Internet, it is your router dropping your outgoing packets. ... It is the numerous connection requests from Transmission that is interpreted as a SYN flood of course. When testing i used only 2 torrents, with few peers per torrent (around 10), (settings: max global 100, max new conn 50) I find it strange that these few connections should cause the firewall to block packets. Another thing is that I get decent speeds with the firewall enabled. The firewall is blocking outgoing connections, how is this possible? But I guess it is from incoming connections (since the router is still letting these pass through) to the forwarded port. Thinking about the SYN flood filter in my firewall, I think it is safe to turn off. Since my bandwidth is about 20MBit I guess if someone tries to DoS my router with a SYN flood, the bandwidth will be filled either way? And I guess my ISP has similar (more expensive) filters in their system. 03-19-11 was still seeing IE connection fails, 'syn flood' messages on SMC2804WRBP-G router web interface (security log), changed transmission config peer-limit-global from 100 to 55 I already have DoS protection disabled, but thanks for your reply. I am now trying to enable DMZ for the unRAID server and check whether the problem is fixed or not. Update: Enabling DMZ resulted in little to no improvement.
February 17, 201214 yr i replaced the firmware on my router for dd-wrt and set QoS for bt and newsgroups to BULK, dns/voip to high and http to normal. I can max out my line (50mb) with bulk, but as soon as http requests are made, these are given priority. Now, I dont notice any slow down of web traffic. Before I had the same problem as you.
May 7, 201313 yr tranmission also kills my internet. tried limiting the number of connection to 10(both global and torrent), still no use. torrent speed is extremely slow and internet browsing is extremely slow. disabling transmission gets me 4 mbps. with transmission on 1 torrent with global caps of 10 connection, my torrent speed is 50kbps. my internet speed is less than 1 mbps. i loss the other 3mbps just like that. are there any better alternative?
May 7, 201313 yr Just found this old thread ... I see a very large number of dropped rx packets on unRAID when certain processes are active - Transmission is one of those which provokes the problem. Do repeated 'ifconfig eth0' commands on your unRAID server and see whether you are also getting packets dropped. Sometimes, when I telnet into my server, it takes ten seconds before the login prompt is displayed.
May 7, 201313 yr All the problems I've ever encountered with Torrents making internet connections slow were to do with the router not being able to deal with the traffic. When you start a torrent you're basically asking the peers/seeds to DDos you. When they start sending to you, once your number of connections is maxed out, your computer doesn't accept new ones. But if your router can't handle all the connections, it's impossible for the computer behind the router to decline them. Millions of people use torrents without issue, so it's not the software. Lots of routers have horrible firmware on them. I'd recommend looking for a router that can run DDWRT, Tomato (my preference), or OpenWRT.
June 10, 201313 yr Being playing with torrents for a while now, one thing i always forget to do after setting up a fresh machine with utorrent or torrent program - is limit the upload limit - change from unlimited to 1-3 kbs - it will take longer to seed, but your bandwidth wont be choked by you unlimited upload... hope this helps
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