Hello Craig, On Sat, 2012-08-04 at 08:59 +1000, Craig Sanders wrote:
On Fri, Aug 03, 2012 at 09:45:57PM +1000, Allan Duncan wrote:
I suggest you read this first: http://www.internode.on.net/support/faq/tech_space/mpls_traceroute/
It won't help you with your download problem, but it helps explain strange numbers when MPLS gets invovled.
well spotted.
Mark might also want to try mtr rather than traceroute. It can display MPLS labels (press "u" in the curses interface or use "-e" on the command line)
Will need to sort out a small matter of removing an old kernel, and the modules. A script in the kernel package removed the modules package, before Apt/Synaptic could do. I need to clear that before I can install a package that provides mtr.
i usually use the --curses mode but the --report mode is more like traditional traceroute (and IMO more readable)
e.g.
$ mtr -e --report --report-wide download.linuxjournal.com HOST: ganesh Loss% Snt Last Avg Best Wrst StDev 1.|-- nexthop.vic.iinet.net.au 0.0% 10 14.6 14.2 13.8 14.6 0.3 2.|-- te7-2.mel-pipe-bdr1.iinet.net.au 0.0% 10 14.5 14.2 13.9 14.8 0.3 3.|-- xe-0-1-0-0.syd-ult-core1.iinet.net.au 0.0% 10 24.7 24.4 23.9 25.0 0.3 4.|-- te3-1-0.bdr1.syd7.internode.on.net 0.0% 10 23.7 23.5 22.7 24.7 0.5 5.|-- po3-0-0.bdr1.sjc2.internode.on.net 0.0% 10 205.9 205.9 205.4 206.3 0.3 6.|-- te1-7.bbr01.eq01.sjc01.networklayer.com 0.0% 10 204.8 204.2 203.7 204.8 0.4 7.|-- ae7.bbr02.eq01.sjc02.networklayer.com 0.0% 10 205.5 205.7 205.3 206.2 0.3 | +-- [MPLS: Lbl 356132 Exp 0 S 1 TTL 1] 8.|-- ae0.bbr02.cs01.lax01.networklayer.com 0.0% 10 212.5 212.8 212.4 213.2 0.3 | +-- [MPLS: Lbl 308816 Exp 0 S 1 TTL 1] 9.|-- ae7.bbr01.cs01.lax01.networklayer.com 0.0% 10 213.7 213.9 212.4 220.7 2.5 | +-- [MPLS: Lbl 567317 Exp 0 S 1 TTL 1] 10.|-- ae19.bbr01.eq01.dal03.networklayer.com 20.0% 10 241.7 241.6 241.3 242.0 0.3 11.|-- po31.dsr01.dllstx3.networklayer.com 0.0% 10 243.3 243.8 243.2 246.8 1.1 12.|-- te4-1.dsr01.dllstx2.networklayer.com 10.0% 10 241.7 243.3 241.2 254.0 4.1 | +-- [MPLS: Lbl 13666 Exp 0 S 1 TTL 1] 13.|-- te3-1.car16.dllstx6.networklayer.com 10.0% 10 244.6 244.6 244.3 245.2 0.3 14.|-- saratoga.site5.com 10.0% 10 239.8 239.9 239.6 240.5 0.3
I think Mark has mentioned problems downloading the Linux Journal before. Makes me wonder what the MTU and MRU on his PPP interface is and whether he (or Telstra) is blocking ICMP packets (in particular ICMP Fragmentation Required msgs).
The MTU and MRU were as default on install. I have now altered both to 600 in /etc/ppp/options, but will only see what effect when I next connect, probably Monday evening. Since it is a local call fee each connect, I tend to do only once a day.
Mark, try setting the MTU and MRU to some fairly low value (the default of 1500 is too big for a 56K modem connection anyway). something like 600 or 900 each perhaps. and then see if the download works.
I will try, and report.
IF this works, there'll be a bit more throughput loss to packet overhead (more and smaller packets) but a slightly slower download that works is better than one that doesn't :)
I am still looking for where there might be any proxy set up, or whether it might be something auto set up by the negotiations when I connect.
it's been far too long since i had a modem connection, i can't remember what I used to set mine at. 600 is a good test value - if that doesn't help then MRU and MTU issues are not the source of the problem and there's no point wasting time trying to find the highest value that works reliably (just set them back to default values). If it does help then gradually increase them (in increments of 50 or 100) until the download stops working again - you have now discovered a good value for MTU and MRU for your connection.
I can look up man pages, and read them, but they are not entirely meaningful at this time. I have other things in life, and a bit of comment from more experienced users does help a lot. I would appreciate whether the files listed in the pon/poff man page are sufficient, or whether I should dig further to set up dialup on Debian 6. I would also appreciate pointers as to the primary package to remove to uninstall Gnome Net Manager. I have looked with Synaptic, but not quite certain of the right candidate. The other matter is how to know whether I need chap or pap, or should set up both.
craig
Regards, Mark Trickett