[Dorset] Bizarre networking problem
At least, I think it's bizarre. The problem concerns the ability of a laptop to connect to NFS shares on two desktop computers DTa and DTb. I am starting migration of my computers from Mandriva to OpenMandriva. Environment is: DTa runs Mandriva 2011.0 DTb runs OpenMandriva 2013 Laptop runs OpenMandriva2013. Wireless router is connected to: PLA 1 (powerline adaptor HP500), which connects to PLA2 (powerline adaptor HP500) and PLA3 (powerline adaptor HP200), which are geographically separated. PLA2 connects to Netgear hub which connects to DTa DTb. PLA3 connects to Laptop. In this configuration, Laptop CANNOT ping DTa or DTb, let alone connect to the required shares. In this configuration, LaptopCAN see the router, and it CAN connect to the internet. When I connect Laptop by cable directly to wireless router, it sees and connects to the required shares. When I move the Laptop to connect by cable to the Netgear hub, it sees and connects to the required shares. The situation is completely reproducible - as soon as I connect the laptop via PLA3, I lose the access; as soon as I remove the cable from PLA3 and plug it into the router, access returns. The inference is that the PLA1 - PLA3 leg is somehow selectively blocking access to the other leg of the LAN. However.. When DTa, DTb and Laptop all ran Mandriva 2011, there was no such problem. (Don't ask about wifi connection between Laptop and wireless router - that's another problem I have to solve; it was working when Laptop ran Mandriva 2011!!) Installed Wireshark but can't use it - video problem Installed Angryip - just confirms the above. Can someone suggest other tests to identify and resolve the problem? TIA Graeme -- Next meeting: Bournemouth, Tuesday, 2014-02-04 20:00 Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/ New thread on mailing list: mailto:dorset@mailman.lug.org.uk How to Report Bugs Effectively: http://goo.gl/4Xue
Re: [Dorset] Bizarre networking problem
On 20/01/14 12:56, Graeme Gemmill wrote: At least, I think it's bizarre. The problem concerns the ability of a laptop to connect to NFS shares on two desktop computers DTa and DTb. I am starting migration of my computers from Mandriva to OpenMandriva. Environment is: DTa runs Mandriva 2011.0 DTb runs OpenMandriva 2013 Laptop runs OpenMandriva2013. Wireless router is connected to: PLA 1 (powerline adaptor HP500), which connects to PLA2 (powerline adaptor HP500) and PLA3 (powerline adaptor HP200), which are geographically separated. PLA2 connects to Netgear hub which connects to DTa DTb. PLA3 connects to Laptop. In this configuration, Laptop CANNOT ping DTa or DTb, let alone connect to the required shares. In this configuration, LaptopCAN see the router, and it CAN connect to the internet. When I connect Laptop by cable directly to wireless router, it sees and connects to the required shares. When I move the Laptop to connect by cable to the Netgear hub, it sees and connects to the required shares. The situation is completely reproducible - as soon as I connect the laptop via PLA3, I lose the access; as soon as I remove the cable from PLA3 and plug it into the router, access returns. The inference is that the PLA1 - PLA3 leg is somehow selectively blocking access to the other leg of the LAN. However.. When DTa, DTb and Laptop all ran Mandriva 2011, there was no such problem. (Don't ask about wifi connection between Laptop and wireless router - that's another problem I have to solve; it was working when Laptop ran Mandriva 2011!!) Installed Wireshark but can't use it - video problem Installed Angryip - just confirms the above. Can someone suggest other tests to identify and resolve the problem? TIA Graeme I think the first thing I would try is swapping PLA3 and PLA2. I don't know the difference between an HP200 and HP500, but that might reveal something. Peter -- Next meeting: Bournemouth, Tuesday, 2014-02-04 20:00 Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/ New thread on mailing list: mailto:dorset@mailman.lug.org.uk How to Report Bugs Effectively: http://goo.gl/4Xue
Re: [Dorset] Bizarre networking problem
Hi Graeme, One thing that jumps out at me is that the HP200 and HP500, (I'm assuming that these names refer to Home Plugs running at 200 and 500 Mb/s respectively), are not properly matched for speed, so when they work they are presumably throttling the whole system down to 200 Mb/s, this alone probably isn't the cause of your problem, but possibly the newer OpenMandriva might be trying to operate at 500 Mb/s and this would probably cause the HP200 to block those communications. If this is anywhere near the mark replacing the HP200 with another HP500 might solve the problem. In the meantime, taking Peter's suggestion a stage further and selectively moving the HP200 around the system and seeing what effect it has at each location could shed some light on things. I have a horrible feeling that somebody will now come and shoot my idea down in flames, I would just ask them to be gentle with me :-) On 20 January 2014 15:45, Peter Merchant wrote: > On 20/01/14 12:56, Graeme Gemmill wrote: > >> At least, I think it's bizarre. >> The problem concerns the ability of a laptop to connect to NFS shares on >> two desktop computers DTa and DTb. >> I am starting migration of my computers from Mandriva to OpenMandriva. >> Environment is: >> DTa runs Mandriva 2011.0 >> DTb runs OpenMandriva 2013 >> Laptop runs OpenMandriva2013. >> Wireless router is connected to: >> PLA 1 (powerline adaptor HP500), which connects to >> PLA2 (powerline adaptor HP500) and >> PLA3 (powerline adaptor HP200), which are geographically >> separated. >> PLA2 connects to >> Netgear hub which connects to >> DTa >> DTb. >> PLA3 connects to >> Laptop. >> In this configuration, Laptop CANNOT ping DTa or DTb, let alone connect >> to the required shares. >> In this configuration, LaptopCAN see the router, and it CAN connect to >> the internet. >> When I connect Laptop by cable directly to wireless router, it sees and >> connects to the required shares. >> When I move the Laptop to connect by cable to the Netgear hub, it sees >> and connects to the required shares. >> The situation is completely reproducible - as soon as I connect the >> laptop via PLA3, I lose the access; as soon as I remove the cable from PLA3 >> and plug it into the router, access returns. >> The inference is that the PLA1 - PLA3 leg is somehow selectively >> blocking access to the other leg of the LAN. >> However.. >> When DTa, DTb and Laptop all ran Mandriva 2011, there was no such problem. >> (Don't ask about wifi connection between Laptop and wireless router - >> that's another problem I have to solve; it was working when Laptop ran >> Mandriva 2011!!) >> Installed Wireshark but can't use it - video problem >> Installed Angryip - just confirms the above. >> Can someone suggest other tests to identify and resolve the problem? >> TIA >> Graeme >> > I think the first thing I would try is swapping PLA3 and PLA2. I don't > know the difference between an HP200 and HP500, but that might reveal > something. > > Peter > > > -- > Next meeting: Bournemouth, Tuesday, 2014-02-04 20:00 > Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/ > New thread on mailing list: mailto:dorset@mailman.lug.org.uk > How to Report Bugs Effectively: http://goo.gl/4Xue > -- Cheers Peter -- Next meeting: Bournemouth, Tuesday, 2014-02-04 20:00 Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/ New thread on mailing list: mailto:dorset@mailman.lug.org.uk How to Report Bugs Effectively: http://goo.gl/4Xue
Re: [Dorset] Bizarre networking problem
On 20/01/14 20:24, Peter Washington wrote: On 20/01/14 12:56, Graeme Gemmill wrote: At least, I think it's bizarre. Can someone suggest other tests to identify and resolve the problem? TIA Graeme, just a slight aside from me on the powerline devices. I use these to connect several devices to home networks but recently they near drove me mad with similar networking oddities that you seem to be experiencing. Changes to the noise levels on the building wiring can really mess up something that may have been previously working. I have a recent problem where the network between my office (outbuilding) and house (where ADSL terminates) only works if I have two of these devices operating. Previously I also had media player and camera plugged in elsewhere. If I plug in another one locally it seems to desensitize the local ones to the remote device (previously this worked). I even bought more devices to test as recent storms seem to have knocked out my surge protectors. Just a though but these devices sometimes stop working in odd ways. Cheers Si -- Next meeting: Bournemouth, Tuesday, 2014-02-04 20:00 Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/ New thread on mailing list: mailto:dorset@mailman.lug.org.uk How to Report Bugs Effectively: http://goo.gl/4Xue
Re: [Dorset] Bizarre networking problem
Hi Graeme, > Wireless router is connected to: > PLA 1 (powerline adaptor HP500), which connects to > PLA2 (powerline adaptor HP500) and > PLA3 (powerline adaptor HP200), which are geographically > separated. > PLA2 connects to > Netgear hub which connects to > DTa > DTb. > PLA3 connects to > Laptop. I read that as 1 fail: laptop -- pla3 -- pla2 -- netgear -- (dta, dtb) > When I connect Laptop by cable directly to wireless router, it sees > and connects to the required shares. 2 ok:laptop -- router -- pla2 -- netgear -- (dta, dtb) > When I move the Laptop to connect by cable to the Netgear hub, it sees > and connects to the required shares. 3 ok:laptop -- netgear -- (dta, dtb) > In this [1] configuration, Laptop CANNOT ping DTa or DTb, let alone > connect to the required shares. Pinging by IP address, not by name? What's the ARP cache show before, i.e. when you haven't tried for a while, and after. See arp(8). > The inference is that the PLA1 - PLA3 leg is somehow selectively > blocking access to the other leg of the LAN. It seems from the above diagrams that more than one pla# breaks it. I know nothing about these things. Perhaps the ARP broadcast is only making it across one of them? > However.. When DTa, DTb and Laptop all ran Mandriva 2011, there was > no such problem. Seasoned admins know to be skeptical of a "Nothing" answer to "What's changed?" :-) > Installed Wireshark but can't use it - video problem tcpdump(8) can still be helpful, e.g. you can watch for ARP packets with it; `sudo tcpdump arp'. Cheers, Ralph. -- Next meeting: Bournemouth, Tuesday, 2014-02-04 20:00 Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/ New thread on mailing list: mailto:dorset@mailman.lug.org.uk How to Report Bugs Effectively: http://goo.gl/4Xue
Re: [Dorset] Bizarre networking problem
Well, you could have knocked me down with a feather. I've lost Digest Vol 521 Issue 1, so I can't find who suggested swapping PLA2 and PLA3. With no expectation of success, I did, and the laptop then connected with the wider Internet and the DTa/DTb part of the network. What's more, when I reverted to the original configuration, the laptop continued to connect! In the spirit of scientific enquiry, I then switched the laptop off for 5 minutes. On restarting, the connection did NOT come up again, so I suppose if I want to maintain a cable connection with OpenMandriva, I'll have to buy a faster HomePlug. On the good side, I've found the driver for the wireless card which is now working, and since Management's opinion is "the fewer cables the better", I'm not in any hurry (just looked at the Solwise site - they're less than £23 each now) Ralph: You asked the Admin question: What's changed? From what I can see, there's a newer version of the tg3 driver in OpenMandriva (or at least a newer date) so I suppose that's it. Anyway, it's been a diverting couple of days. Case closed? Regards to all Graeme -- Next meeting: Bournemouth, Tuesday, 2014-02-04 20:00 Meets, Mailing list, IRC, LinkedIn, ... http://dorset.lug.org.uk/ New thread on mailing list: mailto:dorset@mailman.lug.org.uk How to Report Bugs Effectively: http://goo.gl/4Xue
