Odd router setting blocking site access?
 

Hi folks, here's one I've been struggling with for a while and thought someone here might have an insight.
Ex Ntl area, running wired off a wireless router behind a Superhub in modem mode.
I have had trouble reaching one website, Barco.com , for perhaps the last year. The site is fine and works from mobile and anywhere else I have tried.

I am no networking expert, but have tried a few things. A tracert seems not to get beyond my Superhub.

Tracing route to barco.com [81.247.254.134]
over a maximum of 30 hops:

1 <1 ms <1 ms <1 ms 192.168.0.1
2 cpcxxxx-oxfd25-2-0-cust81.4-3.cable.virginm.net [81.110.xxx.xxx] reports:
Destination host unreachable.

If I remove my router and reset the Superhub to router mode, then I can accesss the site with no problem. Switch back and the problem returns. Hmm, so my router or the Superhub in modem mode is blocking something? So checking the settings in the router the only thing that seems likely is a page called "static routing tables" with the following entries,

Destination IP Subnet Mask Gateway Metric Interface
192.168.0.0 255.255.255.0 0.0.0.0 0 br0
81.0.0.0 255.0.0.0 0.0.0.0 0 eth2.2
0.0.0.0 0.0.0.0 81.109.124.1 1 eth2.2

These are non editable and not something I have set anywhere. If I factory reset the router the 81.xxx.xxx.xxx entries go away until I connect to the Superhub again at which point they reappear. So is this table is being populated from the Superhub?

My only clue/suspicion is the fact that both my ip address and the site address are in the 81.xxx.xxx.xxx range. Is it likely/possible that the entry for 81.0.0.0 Destination IP is thinking that all 81.x addresses are only on the Virgin network and is somehow being routed differently and not getting out to the real world? Told you I'm not an expert! This appears to be the only site I have trouble with and it used to be fine perhaps a year ago with the same setup.

Don't go there that often, but finally got round to trying to find out why! I haven't knowingly tried to access any other 81.x addresses so can't tell if it is the whole block. Obviously I could switch the Superhub to router mode, but it would be nice to get an idea why and if there is some other setting to change, perhaps in the Superhub?

Re: Odd router setting blocking site access?
 

the page loads immediately and I am also using the shub in modem mode. When it is modem mode the shub doesn't do anything at all, especially populate routing tables. What your routing table is basically doing is saying that anything and everything needs to head out to 81.109.124.1 (the ip address of your outside VM cmts to which you are connected) and then from there it will route your traffic accordingly. The problem you have got is that you are getting it out to the cmts, it is after that that there is a problem. The interesting thing is that even though you say it works fine in router mode, it is in router mode that your trace route fails.


C:\Users\General Maximus>tracert www.barco.com

Tracing route to www.barco.com [81.247.254.134]
over a maximum of 30 hops:

1 <1 ms <1 ms <1 ms CORE-ROUTER [18.19.1.1]
2 * * * Request timed out.
3 11 ms 11 ms 12 ms nott-core-2b-xe-1132-0.network.virginmedia.net [62.255.231.69]
4 * * * Request timed out.
5 * * * Request timed out.
6 14 ms 15 ms 14 ms popl-bb-1b-ae0-0.network.virginmedia.net [62.254.42.90]
7 17 ms 15 ms 16 ms m674-mp2.cvx1-b.lis.dial.ntli.net [62.254.42.162]
8 16 ms 16 ms 14 ms ix-7-0.tcore2.LDN-London.as6453.net [80.231.62.5]
9 37 ms 28 ms 29 ms if-26-2.tcore1.LDN-London.as6453.net [80.231.62.58]
10 27 ms 32 ms 26 ms if-17-2.tcore1.L78-London.as6453.net [80.231.130.129]
11 29 ms 28 ms 27 ms if-3-6.tcore1.PYE-Paris.as6453.net [80.231.130.86]
12 29 ms 31 ms 29 ms if-2-2.tcore1.PVU-Paris.as6453.net [80.231.154.17]
13 27 ms 28 ms 31 ms if-32-2.thar1.B1D-Brussels.as6453.net [195.219.241.10]
14 * * * Request timed out.
15 34 ms 37 ms 37 ms lag-26-1000.iprmar1.isp.belgacom.be [91.183.246.140]
16 42 ms 39 ms 35 ms 173.246-183-91.adsl-static.isp.belgacom.be [91.183.246.173]
17 37 ms 35 ms 36 ms 213.181.52.1
18 * * * Request timed out.
19 * * * Request timed out.
20 * * * Request timed out.
21 * * * Request timed out.
22 * * * Request timed out.
23 * * * Request timed out.
24 * * * Request timed out.
25 * * * Request timed out.
26 * * * Request timed out.
27 * * * Request timed out.
28 * * * Request timed out.
29 * * * Request timed out.
30 * * * Request timed out.

Trace complete.

Re: Odd router setting blocking site access?
 

I think you are right - increase your status to networking expert :)

The netmask that Virgin is providing looks wrong and this causes your router to believe it can access that website directly without going via Virgins gateway at 81.109.124.1.

Can you try a release and renew of your WAN side address on the router?
What are the details shown on the WAN address page (net mask and gateway)

Can you check the WAN details on the SH when in router mode?

Re: Odd router setting blocking site access?
 

Thanks for taking a look.

Eeeps said,
My apologies, but this may be a result of cut'n'paste gathering over a few days. A fresh set today shows the net mask to be in the same block as the Wan IP, which I think is where it should be and may have caused confusion.

A release and renew on my router returns with the same settings and the tracert fails at the same point.

WAN IP 81.110.180.82
Subnet Mask 255.0.0.0
Gateway 81.110.180.1

Static Routing Table,
Destination IP Subnet Mask Gateway Metric Interface
192.168.0.0 255.255.255.0 0.0.0.0 0 br0
81.0.0.0 255.0.0.0 0.0.0.0 0 eth2.2
0.0.0.0 0.0.0.0 81.110.180.1 1 eth2.2

Tracing route to www.barco.com [81.247.254.134]
over a maximum of 30 hops:

1 <1 ms <1 ms <1 ms 192.168.0.1
2 cpc69054-oxfd25-2-0-cust81.4-3.cable.virginm.net [81.110.180.82] reports:
Destination host unreachable.

Trace complete.

Switching the Superhub to router mode obviously gives a different Wan IP, though still an 81.xx, but I can see no similar net mask info in the extensive advanced settings page on the Superhub. And of course I can reach the site.

General Maximus,
Just to be clear, it works with the Superhub in router mode, but not in modem mode with my router as well.

Re: Odd router setting blocking site access?
 

It would help if we knew which router you are using as there's obviously something wrong somewhere.

Re: Odd router setting blocking site access?
 

have you got a vpn you can use so you can see if it still works in modem mode and it is a routing issue on VM's side?

Re: Odd router setting blocking site access?
 

The router is a cheapy Tenda W302R.

No vpn I'm afraid, but it had crossed my mind to try. Have to look at that.

Trying to find another site in the 81.xx block would be another. Not sure how to do that though, without trying randomly.

Or I could ditch my router and just use the Superhub, but I like to try and work out why things don't or stop working!

Re: Odd router setting blocking site access?
 

if you have got some dosh to spare have a read of the sixth post down in this thread

http://www.cableforum.co.uk/board/12...ne-gaming.html

Re: Odd router setting blocking site access?
 

If you just want to test with a vpn the you could use tunnel bear for free with 500MB every month. Not a lot of allowance but enough for testing purposes.

Re: Odd router setting blocking site access?
 

Have you tried keeping the hub in modem mode and plugging your pc/laptop directly into it? Test with that, if it works then we know it's your router at fault.

Re: Odd router setting blocking site access?
 

Let's not suggest the guy buys a new router, shall we?

It looks as though the DHCP scope he has has been messed up.

I'll raise it.

Re: Odd router setting blocking site access?
 

That net mask is very wrong. Should be something like 255.255.255.0 or 255.255.254.0

Are there any firmware updates for your router?

Re: Odd router setting blocking site access?
 

So, much scrabbling behind the desk and reboots etc. (So many spiders and all down there! Who knew?)...
Good call, hadn't tried that! Yes it does. Checking an ipconfig/all like that gives
IPv4 Address. . . . . . . . . . . : 81.109.94.62(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.252.0
Lease Obtained. . . . . . . . . . : 03 August 2015 13:57:39
Lease Expires . . . . . . . . . . : 03 August 2015 14:57:39
Default Gateway . . . . . . . . . : 81.109.92.1

Different IP address again, but the subnet mask looks more reasonable.
Patch my router in again, more spiders, more reboots and
Downloads VPN. Bingo! connects straight away. Disconnect vpn and unreachable. Remember this only this one 81.xxx address that is giving problems.

That was and is my thought. Disconnect the WAN from my router whilst looking at the Static Routing Table page and it clears, reconnect and it repopulates, presumably with DHCP data being served from the Superhub.

Destination IP Subnet Mask Gateway
81.0.0.0 255.0.0.0 0.0.0.0

This is the line that I keep coming back to. What is it saying and why is it there? (and why can't I make make any sort of spacing or tabbing make it more legible!?) Surely this is coming from the Superhub rather than being read/interpreted wrongly by the router? It is certainly not editable by me anywhere that I can see. Still feels like it says any attempt to access an 81.xx address will be routed away and dealt with differently. Really could do with trying to access another site that has an 81.xx address.
One link that 404s. Others available, but apparently no route from this version. Not about to risk bricking it for one website ATM:)

Thanks for the all help and clues, you always miss something!

Re: Odd router setting blocking site access?
 

I have a thought - can you change the WAN MAC address of your router?

You could do worse than cloning the MAC from the network card of the PC you used :)

Re: Odd router setting blocking site access?
 

Trys that. No change there I'm afraid. Think I tried that and changing the DNS when I was first looking some while back.

Re: Odd router setting blocking site access?
 

Okay that's interesting. I know what Igni is getting at and was going to be my next suggestion.

Here's the thing - there's a chance that your router got unlucky and happened to get a DHCP lease with a bad configuration. Just pure bad luck that could have happened to anyone.

However.

The fact that other devices are getting good leases and when you clone the mac of your PC, you're still getting a bad subnet, suggests that the router is at fault. There's no reason the DHCP server at Virgin would be handing out a good config and a bad config to the same MAC.

Unless you can override that, I think your router needs to be replaced.

Re: Odd router setting blocking site access?
 

ya, especially as it is working on the shub out of all things (twilight zone)

Re: Odd router setting blocking site access?
 

So, I've cracked it. I think!

Firstly the router page I said was called "Static Routing Table" is just actually called "Routing Tables" and appears to populate from the DHCP as in previous posts.

There is however another page below called "Static Route" which allows you to input your own routes. But how do you know what?

Well a bit of logic and trial and error, I tried this,

81.0.0.0 255.0.0.0 81.110.180.1

Now the routing table says,

Destination IP Subnet Mask Gateway Metric Interface
192.168.0.0 255.255.255.0 0.0.0.0 0 br0
81.0.0.0 255.0.0.0 81.110.180.1 0 eth2.2
81.0.0.0 255.0.0.0 0.0.0.0 0 eth2.2
0.0.0.0 0.0.0.0 81.110.180.1 1 eth2.2

Low and behold I can now access the site! I think I have now forced any 81.xx addresses to be routed to the Virgin gateway. Remove the static route and it fails again.

So, is this the right way to do it? What else may it break? Presumably it will only last as long as this lease holds and then a new gateway is set? And still, where does the original 81.xx route come from and why? Is this just a grade A kludge?

Your last post Kushan, got me thinking again to have another look.

Many thanks for all your inputs, happy to have any more clues as to why.

Every day is a school day, they say. This networking malarkey is easy isn't it? /runs and hides/

Re: Odd router setting blocking site access?
 

it isn't going to break anything because all it is doing is telling everything to go to the cmts which is what it should be doing anyways

Re: Odd router setting blocking site access?
 

It'd be better to do it the other way round. Copy the WAN MAC of your router to your PC's network card.

You should then get the same IP as the router got, and the subnet mask you receive in that situation will confirm if the router or VM's network is the issue. Though I guess it's fairly obvious already.

---------- Post added at 13:11 ---------- Previous post was at 13:10 ----------

Well technically it's still a broken routing table. And a device that ignores the subnet mask in a DHCP lease is... broken.

Re: Odd router setting blocking site access?
 

Well that took a bit of fiddling to find, but I think I managed it, at least ipconfig reported the MAC address changing. However the end result seemed to be that it still need the extra static route to make it work.