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View Full Version : AEBS DHCP Fails Outbound Connections




mainstay
Jul 19, 2012, 11:33 PM
Scenario:

small office >> AEBS >> webmail server.

WHEN AEBS has default settings we can connect to webmail server (hosted by HostMonster, not an internal host).

WHEN AEBS has a SINGLE DHCP reservation setup, we CANNOT connect to webmail server.

All other settings remain unchanged.

I am stymied here.

I have tested with a second, brand new, off-the-shelf AEBS.

This makes no sense to me.

Any thoughts by someone from a higher pay grade?



AtomicGrog
Jul 20, 2012, 12:17 AM
Scenario:

small office >> AEBS >> webmail server.

WHEN AEBS has default settings we can connect to webmail server (hosted by HostMonster, not an internal host).

WHEN AEBS has a SINGLE DHCP reservation setup, we CANNOT connect to webmail server.

All other settings remain unchanged.

I am stymied here.

I have tested with a second, brand new, off-the-shelf AEBS.

This makes no sense to me.

Any thoughts by someone from a higher pay grade?

Couple of things to try assuming you are sure the web link is actually up...

1) Try to connect to the web server using ip address rather than name.
2) Check the DNS settings you are inheriting from the DHCP reservation.

To me it seems likely the DHCP server configuration is giving out the wrong details. I used to override my DHCP to prioritise my internal DNS over external and I saw exactly the same simptoms when my internal dns failed.

mainstay
Jul 20, 2012, 11:10 AM
Hi AtomicGrog!

Thanks for the feedback =)

>>1) Try to connect to the web server using ip address rather than name.

No change.

2) Check the DNS settings you are inheriting from the DHCP reservation.

We use the DNS values from our ISP: fail and then switched them to use Googles (8.8.8.8 etc.): fail

I have flushed the DNS from the systems after each change so there should be no residual.

We replaced with a DLink (DIR-615) and it worked last night... but not this morning - wth?

Turning off SPI seems to correct it.

For now.

The AEBS does not have SPI, so I can't see this as being an issue.

In 12 years of doing this, I have never seen this.

AtomicGrog
Jul 22, 2012, 06:38 PM
Hi AtomicGrog!

Thanks for the feedback =)

>>1) Try to connect to the web server using ip address rather than name.

No change.

2) Check the DNS settings you are inheriting from the DHCP reservation.

We use the DNS values from our ISP: fail and then switched them to use Googles (8.8.8.8 etc.): fail

I have flushed the DNS from the systems after each change so there should be no residual.

We replaced with a DLink (DIR-615) and it worked last night... but not this morning - wth?

Turning off SPI seems to correct it.

For now.

The AEBS does not have SPI, so I can't see this as being an issue.

In 12 years of doing this, I have never seen this.

If you cant connect directly (i.e. using ip address rather than name in the url) then it's not a dns related issue.

Do you have problems with any other sites?

mainstay
Jul 23, 2012, 07:49 PM
I believe I found a bad name server this afternoon.

It would appear that half of the time we were being routed to the proper site via the working name server and half the time we were being routed to a bad location on the target server.

We have updated the name servers and hope to see it propagate soon.

The crazy part was that when we swapped out the AEBS it DID work... for a few days... and then not.

I also found a really laggy response from the OTHER name server... so we've updated everything to a more direct route.

Will update if I find a definitive solution... as this has been an odd one.