Incoming VOIP and FTP problem.

[yatest9]

Hi,

For the past three or four days we have been able to connect to FTP accounts on various hosts but we can't retrieve directory listings, it just times out.

Out VOIP phones can also dial out but not receive calls.

We've spoken to our VOIP providers and they can't connect to our phones, it times out.

We've share an office with a different company and we get the same problem with their BT connection, implying that it's not a router setup issue as we use different routers.

We have no firewalls enabled on the router or on our machines.

It's a similar problem we had when we first ordered the BT line and it was resolved by getting a fixed IP from BT.

Other clients seem to be having the same issue:

http://community.bt.com/t5/BB-Speed-Connection-Issues/FTP-Access/td-p/100527

I've phoned support and they've said they've made no changes and it's nothing they can do but something must have changed at BT's end as it's been working fine for 6 months.

Any ideas?

[stchedro]

Are you using the BT Router?

If so which one and which firmware version.

The biggest problem with using the BT kit is that it upgrades firmware on command from BT central and this often stuffs up settings.

My best advice is to using something that is properly made for VDSL use Draytek 2750 and ADSL or ADSL2+ use Netgear.

That way you and not somebody in India is in control of your router settings.

[gugaguga]

Hi. Was the connection working before with the same router that you are using currently? Can you ping the FTP server at least? If not, run a traceroute for us to check where the farthest hop is. 

[yatest9]

We're not using a BT router, it's a Belkin.

The other connection we tested is a BT router. Same results.

We can ping the FTP server it's the packets sent back that seem to be failing.

From an external server, I cannot PING our IP, could that be the problem?

[yatest9]

Does anyone know how I can prove incoming data doesn't reach our IP / Router on certain ports?

I have SSH access to several external servers I can tracert / ping from, but ports can't be done on in a tracert.

[OldWolf]

Hi,

You could try http://ping.eu.  It sends packets to a port on a specific IP and tells you if they get blocked.  It's normally used for testing firewalls.

Hope that helps.

Dave A

[MHC]

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@stchedro wrote:

That way you and not somebody in India is in control of your router settings.

---

Why would somebody in India be in control of the settings?

As far as I know, Scotland has not gained independence from the UK and moved allegiance to te sub-continent!

[yatest9]

Hi,

The solution to our problem was to change the MTU from the default of 1432 to 1500

No idea why we had to make that change to get it working.