BT voyager 205 router

Troubleshooting the BT Voyager 205 adsl router modem

The main 205 page has loads of great comments and questions on it, some repeatedly!   Here are the most common issues, and their solutions..

These solutions assume you have read the main voyager articles, assigned a static IP to your computer that is on the same subnet as the router, with the correct netmask, etc, as described on the main page. Only a fool would begin here!


I can't get to the web interface!

First, ensure the router is powered up and physically connected to the computer you are trying to access it from. The "power" and "dsl" lights should be on, and the "ethernet" light, too, though it flashes on and off when in use.

Next, ensure you are using the correct address, the default is http://192.168.1.1, though certain special people can also access it at http://192.168.1.2

If you can't access it there, it's possible you have overlapped the IP of the router with one of your private computers. Ensure you start numbering those from 192.168.1.3, or else they will conflict with the router. Check out the static IP page for more gory details.

Still no joy? It's highly unlikely, but possible, that LAN web access has been disabled. Issuing the following command would fix that, in a telnet session to the router..

modify mctl access httplanaccess enable

If you still can't access the router, you should definitely leave a comment!


I can't get into the "advanced" pages!

Firstly, ensure you are using the correct username/password combination. The default is admin/admin and unless you've changed it to something else, it will still be that. If you need confirmation, login to a telnet session with the router using admin/admin and see if it works there.

The BT web interace, such as it is (crap), relies on Javascript. Without Javascript you simply can't use it. So ensure you have Javascript enabled in your browser, even temporarily if you're one of those paranoid sorts that keeps it disabled.

If you still can't get the admin pages, it's possible that some other software is interfering with your browser's Javascript processing. The most common suspects are firewalls. So go into your firewall preferences and either disable its Javascript Protection altogether, or create a rule (if such a thing is possible with your particular firewall) allowing all Javascript from 192.168.1.1

You can even disable your firewall altogether (temporarily) to see if this fixes it. If it does, you know it's the firewall messing with your javascript. Same goes for pop-up blockers, keen anti-virii, and other similar software. Switch them off for a minute and try again. If you find something really unusual blocking access, let us know! If disabling all your "security" software doesn't fix it, the trouble is surely elsewhere.

You might want to check out the note (above) about overlapping IP addresses, which can curiously interfere with admin access too, apparently.

Still not working? It's possible that your (Windows) browser cache isn't being updated correctly. So go into your "Internet Options" control panel and ensure that your browser is checking for "newer versions of stored pages" either automatically, or Every visit to the page. Clear your internet cache and try try again.

Lastly, just keep clicking the "Advanced" link, no really, Digitaldazz swears by this! And by now you're desperate enough to try anything.

If you still can't access the Advanced pages, screw it! Go watch Robocop or something and come back later. You don't really need the web interface, not only is telnet quicker, but lots of the good stuff isn't available from the web pages anyway.

You might also want to check out the public archives for Mackila's configurateur app. Good stuff.


My router keeps disconnecting all the time!

I have only one thing to say about this.. UNPLUG THE USB!

All the tips, tweaks, tricks and recommendations on these pages are for ethernet connexions. USB is too troublesome, too problematic to attempt to support. Get a NIC (Network Interface card) for your computer and save yourself a lot of potential headaches. A NIC can be had for around £2-£3, so you really have no excuse.

Briefly, the reason USB is such a Bad Idea, is that in order to use the router in USB mode, you need to load drivers onto your computer. The router then becomes a peripheral of the computer, and will use up system resources, sometimes a lot of them. If your system gets bogged down in any way your internet connexion will suffer and ultimately break.

Ethernet you just plug in, and as computers already know how to "talk ethernet", no extra resources are required. Even rebooting your computer won't affect your internet connexion.

Once you have a proper ethernet connexion, issue these commands in a telnet session, they will ensure you stay connected at ALL times..

modify ppp global keepalive enable
modify ppp global pppsesstimer nevertimeout


If you have more than one computer you'd like to access the internet (and that includes other computer devices like Games consoles) then buy a switch box, which is like an ethernet hub, only smarter. You can pick up one of these for £10 (ish) and once you connect your router to this, you have a permanent always-on internet connexion that is available for any device you plug into the switch.

Even if you only have one computer, it's worth having a switch. But first, get ethernet!


I'm uploading HEAPS, but downloading NOTHING!

You need to keep an eye on upload speeds. If you max out your upload bandwidth, it will kill your download capabilities, sometimes completely.

You see, the reason TCP/IP is so reliable is that for every packet you send (or rather, a server sends), an "ACK", or "Acknowledgement Packet" gets sent in response, sort of a "yup, got that, NEXT!". If the server (or any application acting as a server, which includes other bittorrent clients, etc) doesn't receive the ACK, it assumes you didn't get the packet, and re-transmits it. It will also slow the rate of transfer, assuming it is sending them too quickly for you to handle.

Ergo, if you upload capacity is saturated, there's no bandwidth left to send back the ACKs, and your downloads will slow to a crawl, even stop altogether.

In practice, so long as you cap your upload capacity to somewhere around 80% of your total capacity you will have enough space for the ACKs to travel freely, and downloads will be unaffected. For BT broadband (1MB/2MB packages) 25kb/s is a reasonable limit for any p2p application, and the odd spike (created by other net activites) won't cause any real changes in your download speeds.

Remember, this is TOTAL upload capacity for your connexion. If one machine on your network is uploading at 25kb/s and another machine starts uploading at 5kb/s, that equals 30kb/s, and you are once again maxed-out.

If you have family members/flat-mates/whatever that do a lot of p2p sharing, explain the situation to them all, and allot each a fair share of the upload bandwidth which they MUST NOT exceed, for everyone and their downloads' sake.


Whenever I startup (insert app like eMule/KAD/WinMX/etc) everything else dies!

This is similar to the above problem, your capacity has been reached, but this time it is your "Maximum TCP Sessions" limit which has been reached. By default, it's 192. If you tweak it to 512..

modify nbsize maxipsess 512

you can do a whole lot more before your limit is reached. If you have v1.8+ firmware, the limit is 511, not 512.

The next thing you can do about this, is make those old sessions die faster. By default, the voyager will keep these sessions open for quite some time. Some applications; p2p apps, games, etc, can open loads of connexions really quickly (KAD likes to open zillions of connexions), and unless you set a low "timeout", the old ones will keep hanging around, open, preventing you from making new connexions. The simple solution is to reduce the timeouts..

modify nat global udptimeout 20

modify nat global tcpidletimeout 3600

modify nat global tcpclosewait 30

modify nat global tcptimeout 20

commit
   always do this after entering good commands!

These are suggested guidelines. Check page 255 of the cli reference for more details. Experiment to find the values best suited to your internet usage. Game players will probably want to take the UDP timeout right down to maybe 4 or 5. The numbers above should work well for most setups.

note: even with these tweaks, you will still need to limit the maximum number of connexions inside the application. check out the recipes page for details of particular applications.


My webserver isn't working! (good generic troubleshoot)

When troubleshooting network connexions, it's a good idea to start at source, that is, where the request is coming from. Visualise yourself as a packet of data, travelling from the user's browser to your webserver (this works for any network communication). In this example, the data packet's journey begins "outside"; ie. we are testing an incoming connexion.

It's not possible to directly access your server from outside your LAN, as you are already inside, and this router has no "loopback" facility (if you try and load "mydyndomain.ath.cx" in your browser, you will get your router's web interface!). However,there is an indirect way..

Use a proxy server! It's simple and effective. (so simple that folk usually kick themselves when they read this bit!) In much the same way as an online port probe will send a request into our network to test a p2p application, a proxy server can do the same for your webserver, and then, of course, relay the result back to you! In effect, the proxy server is acting as our testing client, we're just watching. clever stuff.

Configure your browser to use any decent proxy server and hit google. If google loads, we can move on. If not, get another proxy and hit google again. I always hit google whenever I load a new proxy. If you don't know of any good proxy servers, see here. If you use firefox, go check this out. Mac OS X users might be interested in this.

Now try to load your website at its dynamic address (site.ath.cx, or whatever). If you get an "address not found", perhaps the dynamic dns isn't pointing to the correct IP, your IP. Check with your ddns provider's config page. You might also want to check out your dynamic hostname using one of the great online DNS tools. If it is pointing to your current IP, the problem must be local, so we move on..

Next the router, our gateway to the internet. Is it stealthed? And no other firewall rules are present? (like that big list of rules that comes with a fresh router)If you reboot the unit, it (annoyingly) inserts some rules automatically. At least one of these will mess up your ability to run a webserver, so remove them! Remove them all! There's a shell script to do that, available here

Next, ensure you have a rule for port 80 allowing incoming traffic.

create ipf rule entry ruleid 808 ifname public dir in act accept transprot eq num 6 destport eq num 80 seclevel high medium low

Then check your NAT rules, is the port 80 rule redirecting traffic to the correct machine? is it TCP?

create nat rule entry ruleid 808 rdr prot num 6 lcladdrfrom 192.168.1.100 lcladdrto 192.168.1.100 destportfrom num 80 destportto num 80

We use ruleid 808 instead of 80 because the router has a nasty habit of deleting ruleid 80.

Check every aspect, make sure something obvious isn't wonky. Often it's the obvious things we overlook. For instance, ensure you have disabled WAN-side web access to the administration interface, as this would almost certainly mess up any attempts to access your private webserver behind the router..

modify mctl access httpwanaccess disable

Next the webserver itself. Can you access it from localhost? (the same machine) From your LAN? Does it work normally? If not, fix it, if it's okay, we can move on..

Is there a firewall running on the server box? It may be allowing LAN traffic, but denying outside traffic. If you are using a virtual host (wise), does it match your dyndns address? like corz.ath.cx does..

From my router configuration..

create ddns hostname ifname ppp-0 name corz.ath.cx
create ddns intf ifname ppp-0 srvcname dyndns username "corz" passwd MyPaSSwORd system dynamic wildcard enable


From my virtual hosts file.. (maybe you keep your virtual hosts in your httpd.conf *tsss* ;o)

ServerName corz.ath.cx
ServerAlias corzorg corzorg.org
etc..


Check everything and test Test TEST! Every step of the way! Approach the issue logically, linearly, and you can't go wrong.


It's still not working!   (a checklist)

the router..

your computer..

your network..

Finally..

If you try all these recommendations and it's still not happening for you, please leave a comment on the main Voyager 205 page, and we'll see what we can do.

have fun!

;o)

Welcome to corz.org!

If something isn't working, I'm probably improving it, try again in a minute. If it's still not working, please mail me!