Topic: D-Link Connections fails

[Matt]

I am quite new to using e-smith so please forgive my ignorance.  I am running e-smith 5.6 as a server gateway dedicated and my ISP has assigned me a static IP address.  My aim was/is to host our website and use the e-smith mail server.  After looking through various posts here I decided to buy an ADSL D-link ethernet modem 300g+ which seemed the most straight foward (cheap) way of making a permanent connection to the internet.  

I had a bit of trouble getting the thing up and running and after checking out a few eariler posts I managed to make the thing work, at least for a few days without any problems.  

However now the connection keeps failing with obvious consequences.  

When I orginally setup the modem I set it up on a windows PC through the web interface provided by the d-link where I saved my ISP user name and password needed to connect,  then put the NIC bach in the e-smith box which seemed to work fine at first.  

When configuring the server's external interface configuration I chose option 4 which is 'use static IP address'  Is this the right option? if not which option should I use?

Can anyone shed any light on why my connection keeps failing?  Are there any more realiable ethernet modems avialble in the UK, because the router option seems too complicated?

Also is there any way of monitoring the connection to the outside world, becasue all I seem to do at the momment is keep sending test emails to people or firing up the internet brower to make sure we are still connected to the world and then being mightly frustrated then the connection doesn't work.  

Any help or suggestions would be most welcome.

Sorry about spelling, grammer..

[Dave Liquorice]

> Can anyone shed any light on why my connection keeps failing?

Does the D-link have any logs you can look at? Pretty poor if it doesn't keep of log of events and their reasons/causes.

> Also is there any way of monitoring the connection to the outside
> world, ...

Quick 'n dirty:

My wireless broadband is a bit shakey (Windows ISA servers in the ISP...). I've written a Perl script that I run on my OS/2 workstation to send 10 pings to the public gateway machine every 30s which changes an icon on my desktop reflecting the result and it keeps a log of each ping session.

Cheers
Dave.

[Andy parkinson]

You should use dhcp to connect to this modem. When not connected to the Internet it always defaults to ip address 192.168.0.1 so make sure that anything on the green side of the SME is not in that range or once you lost the connection you will not be able to access the modem web page to reconnect. I have used several of these modems and I am not impressed. They seem to have lost the connection more than most and the recovery is usually poor combined with the fact that you cannot change the default ip address means that you could end up changing every address on a network.

Andy Parkinson

[Matt]

Andy

Thanks for that info, the company i got the modem from are going to exchange it for something else, do you have any reccomendations for a more realiable modem/router

[THE DON]

Matt,
       The problem is that you are setting the modem to use a static IP.  From the information you have given us it seems like your ISP did not give you a dedicated static IP.  

The solution to your problem is to select DHCP in the modem config page.  As for it disconnecting all the time, you may want to lower your MTU.

The usual DSL default is for the MTU to be set to about 1500, change it to something lower and work your way up until you have a reliable connection.

Hope it helps

DON

[Dave Liquorice]

> The usual DSL default is for the MTU to be set to about 1500,
> change it to something lower and work your way up until you have a
> reliable connection.

Think that should say work your way up until  you have an unlreliable connection again.

I think there is a issue when running PPPoE on DSL, the hedader is larger by a few bytes which causes fragmentation of packets with the normal MTU. This should only impact throughput though not cause the link to drop (but who knows with BT...)

Search for MTU in demon.announce on groups.google.com.

Cheers
Dave.

[Matt]

Don

Thanks for suggestions, I do have a static IP address from my ISP which is BT!!!

How do I lower MTU is this a setting on the modem?

Thanks  Matt

[Matt]

Can anyome let me know how they protect their modem from power failures, which i'm sure don't help with my connection problems.  Do I need to get a UPS to protect my modem and do people have suggestions for cheap ones in can get in the UK,  I have seen other posts that suggest that APC work well with e-smith is that the case?

[Brian Read]

I'm in the UK

I protect my servers with an  APC UPS, as the Linux filesystem can be a little fragile, There is a contribution for it on contribs.org .I wouldn't have thought you'd need to worry about protecting your modem, what can it harm?

Regarding ADSL modems, I use a cheap conexant based one, works fine (Zoom X3 is an example). I run it in NAT/Router mode with a dedicated subnet to my Server, and the needed ports forwarded (including VPN passthrough).  You cannot run modems in "bridge" mode in the UK, as SMEserver does not support pppoa (it supports pppoe). However many of them provide "half bridge" mode which still handles the pppoa protocol, but acts transparently otherwise.  I have briefly tried this, but it locked up my modem, so I haven't dared try it again.

No idea about the Netgear 814, but I am surprised that it doesn't work reliably.  Is it up to date wiith the firmware?

Email me off list if you want more detailed help (brianr at bjsystems.co.uk)

Cheers

Brian