lost wan connectivity when copying files

starmonche · 06-09-2007, 11:20 PM

my roommate has a wireless router that connects to the internet. my slack box has a wireless NIC that shares internet from that connection through a wired NIC to a router where my PCs are connected.

my PCs can see each other and i'm able to copy files amongst them and use the internet fine.

HOWEVER when i copy a large file to a share on my linux box then the internet connectivity for my slack box (and my networked PCs) slows either to a crawl or goes away altogether. when the copying is done (or canceled) the internet connectivity is restored.

to share the internet across my network i run the following:

sysctl -p
iptables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE

and /etc/sysctl.conf is "net.ipv4.ip_forward = 1"

FMC · 06-10-2007, 08:26 AM

You can try to shape the traffic to have a QoS, thats not so easy to do, but it you really need you can search something about CBQ and HTB. CBQ is not that good, but its easier than HTB!

[]'s, FMC!

archtoad6 · 06-10-2007, 09:15 PM

From where are you copying this large file to a share on your linux box? Another of your PC's, your roommate's box, the 'Net?

starmonche · 06-11-2007, 02:25 AM

All of the file copying that I do involves sending things from one of my laptops to my slack server (this is all on my own network).

To get internet before I had an XP box running ICS plugged into the internet port of my router. My slack box runs dhcp and is a file server so it's just connected to a PC port on my router. It occurs to me now that this problem might disappear if I install another NIC in my slack PC and dedicate one card to internet (connected to 'net port on my router) and the other to dhcp/file sharing.

Think that's the problem? If so, looks like I'll be starting a new thread!

archtoad6 · 06-11-2007, 07:01 AM

Absent an ASCII art diagram of your network

; as I understand it, the slack box is the center & choke point. Actually, its connection to your router is the choke point. When you copy a large file you saturate it, leaving little or no bandwidth for internet traffic.

I don't understand exactly how you would connect an add'l NIC, but I agree -- adding a 2nd path for 'Net traffic would probably work.

Why start a new thread?

Is there any way you can connect your router to your roommate's w/o having to go through one of your PC's? BTW, what are the 2 routers? W/ links, please.

tredegar · 06-11-2007, 12:15 PM

Archtoad6 is right - it's the router that is saturated.

Some router/switches are clever than others: I have not had this problem with the Zoom X4, X5 or Netgear GD834G: If one user is gobbling all the bandwidth with a big download, and another needs some, the hog is throttled back and the bandwidth redistributed. So, my advice is to try another router (and please tell us what you are using so we can avoid it!)

archtoad6 · 06-11-2007, 01:00 PM

Actually, I think it's the link between his slack box & his router that is saturated. If I understand his description of his LAN correctly, the slack box sits between the 2 routers (the roommate's w/ the I'net & his for his sub-net) & passes traffic between them. So, both the file copy traffic & the regular traffic to the outside world go through the link between his slack box & his router. I think that is where the saturation is occurring, or did I misunderstand the LAN's topology?

starmonche · 06-11-2007, 01:02 PM

the router with the 'net connection is a linksys wrt54g.

i'm running slack 11 (2.6 kernel) and it's connected to my linksys befsr41 router on a PC port. also connected is my media center PC and a netgear wpn802 wireless access point. then i have a few other PCs connecting wirelessly through my wifi access point.

here's a link to an awesome picture i drew with a diagram of my network:

http://geocities.com/starmonche/network.html

quick edit: copying a dvd image from one wireless laptop to another killed the internet on my laptops...but the slack box was unfazed. making me believe my router won't "guarantee" 'net connectivity unless i connect the 'net to its internet port.

w0rd?

archtoad6 · 06-12-2007, 07:18 AM

Great pic & thanks for bothering w/ the links. I wish more people would provide asked for info. as readily.

Everything, including "but the slack box was unfazed", points the to the slack-to-blue_"thing" link getting saturated. Think about it: "Slack" is connected to the 'Net through a separate link -- its wireless card -- & that is not getting saturated.

I assume that if you could have wired the 2 routers together, you would have.

Does "Wireless repeated mode support with wireless distribution system (WDS)" mean that the Netgear WPN802 could link to the WRT54G to provide your sub-net?
If so, would you have to change your sub-netting IP scheme?
If so, would it, too, saturate under heavy file transfer conditions?

As long as you can get the routing right, I think your own idea of adding a NIC to "Slack" is viable.
Something like this:

Code:

                     \    /
                      \  /  ~ ~ ~ ~ \
   (      )        +--------+        \  +-------------+
 (   'Net   ) ==== | WRT54G |         \ |   "Slack"   |
   (      )        +--------+           | wlan0       |
                                        | .           |
                                        | . dedicated |
                     \    /             | . internal  |
                      \  /              | . route     |
                   +--------+           | .           |
                   | WPN802 | ========= | eth1 (new)  |
                   +--------+           |             |
                     | | | |___________ | eth0        |
                     | | |              |             |
                                        +-------------+

starmonche · 06-12-2007, 09:48 AM

your diagram shows exactly what i'd like to do (and your ascii art rules...takes me back to dos 2.11 days). i'm just not sure how to share 'net on one NIC and use the other for filesharing and DHCP.

connecting an xp box with ICS to the internet port of my router produced no problems (except an extra pc in the living room).

apparently the wireless AP will only work as a repeater from another similar netgear wireless unit. and if i remember correctly WPA wasn't supported on such a link.

so then i guess my question now is how do i share internet through one NIC and dhcp/filesharing through another?

starmonche · 06-13-2007, 02:23 PM

in a moment of clarity it hit me...just bridge wlan0 and eth0 together. the bridge would be its own entity and provide the connectivity that i'm looking for and i could be on my happy way with eth1 doing the dhcp/file sharing for my side of the network.

alas, it was not meant to be. trying to bridge wlan0 and eth0 did something that prevented *anything* from connecting wirelessly to roomie's router. destroyed the bridge and his router was fine. tried to put it up again and *bam* no connections allowed from anything.

is my solution to all of this going to ultimately involve iptables?

archtoad6 · 06-13-2007, 04:40 PM

Thanks for the kind words about the art.

I was thinking of bridging, too; but I don't know a lot about it, what exactly did you do? (Like a Code block, please.)

Maybe a "simple" set of routing table entries would do the trick. I'm off to the HLUG Weekly Linux Workshop & I'll ask there. Also, gotta run or I'll be late.

archtoad6 · 06-13-2007, 08:44 PM

Oops! I just noticed that I condensed your router & airport into 1 box in my diagram, I'm not sure I'll bother to edit it.

Consensus is that routing can do the trick. Needless to say, change the IP's below to match reality.

Assumptions
House LAN - 192.168.1.0/24
wrt54g: 192.168.1.0.1

Pers. LAN - 192.168.2.0/24
befsr41: 192.168.2.1 (LAN ports)

New Link -- 192.168.8.0/24 (or /30)
2-node network -- static IP's
befsr41: 192.168.8.2 (WAN port)
eth1: 192.168.8.1

Code:

ifconfig eth1 192.168.8.1
route add default wlan0
route add 192.168.2.0 eth0
route add 192.168.8.0 eth1

Once again, I am up against a time deadline -- the meeting ends @ 9 -- & must cut this off here.

starmonche · 06-14-2007, 03:41 AM

Quote:

Originally Posted by archtoad6

I was thinking of bridging, too; but I don't know a lot about it, what exactly did you do? (Like a Code block, please.)
late.

brctl addbr lan2lan
brctl addif lan2lan eth0
brctl addif lan2lan eth1
ifconfig lan2lan up

if memory serves that was what worked in the past to connect a cable modem to a linux box and then the linux box to another pc (with a crossover)

obviously in this case i replaced eth1 with wlan0...
this time around i assigned an ip to "lan2lan" so i could try pinging it from either network but i couldn't even see it unless i brought eth0 and wlan0 up before bringing lan2lan up.

i'm using the rt2500 package i got from serial monkey to make my wifi card work (most stable tool so far) but i'm not sure that the WPA link engages unless wlan0 is brought up explicitly (and not just as part of a network bridge)

here in a few minutes i'll give your code chunk a shot. thanks for your interest man.

starmonche · 06-14-2007, 06:07 AM

i tried the lines you suggested after a fresh reboot and i had no connectivity. don't know if it helps, but running the route command (by itself) took a long time to finish.

anyway, i added eth1 and connected it to the wan on my router and left eth0 connected to a lan port on it.

running this variation on what i had before got it working exactly as before (internet drops when copying large files)

ifconfig ra0 192.168.1.90
ifconfig eth0 172.28.201.3
ifconfig eth1 192.168.8.1

route add -net default gw 192.168.1.1 netmask 0.0.0.0 metric 1
sysctl -p
iptables -t nat -A POSTROUTING -o ra0 -j MASQUERADE

dhcpd eth0

i'd cheat and use firestarter to config it all for me but slack 11 doesn't have any gnome in it. grr. anyway, i'm googling right now for route and iptables to see exactly what they do.