We have 2x 8mbit ADSL lines coming in from 2 different ISPs.

The Vigor 2820 inbuilt WAN1 ADSL port is set to just collect mail from one of the ADSL lines, and we have a Netgear modem router plugged into the WAN2 port of the Vigor 2820 that is used for all other activity (web browsing, FTP, remote connection, etc.).

For whaever reason the Netgear connected to port 2 died last weekend, so I replaced it with a similar model and set it up the same... or so I thought.

The Netgear connected to WAN2 has to be in its own IP range, so as we usually use 192.168.0.##, the Netgear is set to use 192.168.1.##.

After replacing the blown Netgear we can browse (albeit noticably slower) most of the time, but at different times in the day we just seem to lose all web access for about 30 seconds at a time.

The actual ADSL connections never drop, they stay logged in to the relevant ISPs too.

Earlier today I discovered that DHCP was turned on on the Netgear on WAN2, so I disabled it hoping that it was that conbfusing the computers on the 192.168.0.## network.

All seemed to be fine then for a few hours, even had better speedsm but then it started dropping again.

I'll plug a laptop straight into the Netgear tomorrow to see what speeds I get there.

Any ideas of what particular settings would be affecting the LAN connections like this?

Maybe a DNS problem?

The strange thing is, is that it happens even if I route all browser through WAN1 or WAN2.

WAN1 is an old Pipex, now automatically rolled over to Opal ADSL account
WAN2 is Eclipse Internet ADSL account.

Any ideas? This is still happening.

I have set Physical Type on both to "100m Full Duplex", and also Load Balance Mode to "According To Line Speed". Active Mode on both is "Always On".

Still the connection seems to drop out intermittantly.

However, yesterday it seemed to cut out everytime I tried uploading a file >1mb via an external email client (Hotmail).

Thanks in advance...

You need to be a bit more specific is the ADSL going down? You can tell that as the up time is different on the ADSL to the router. Or is it the router not passing traffic?

Howard Simpson wrote: You need to be a bit more specific is the ADSL going down? You can tell that as the up time is different on the ADSL to the router. Or is it the router not passing traffic?

I'm not sure how much more info you need. I stated that "The actual ADSL connections never drop, they stay logged in to the relevant ISPs too". So, no they never disconnect from the ISP. It seems as if the router is not passing traffic for up to 30 seconds or so each time.

It seems to be related to whenever people using Macs are sending emails with attachments larger than 500k from Apple's Mail program. They are set up for POP mailboxes over port 140.

Any ideas?

Well it certainly is an obscure one.

1. Have you checked the MTU rate on the new Netgear you put in?
2. Have you checked (or isolated) if this issue occurs with only one provider? (no load balancing at all - just single connectivity)
3. PORTS Speed and Duplex on ALL devices match.

This feels like to me that there is some buffer overrun occurring when larger transmissions occur. Whether that's MTU or LAN Network settings I cannot really say. I would suggest an isolation test and see if it is related to one particular connection or the other.

Please send more information as it becomes available.