Internal ADSL & Linux, current status?

[Nick Clifford]

Hiya,

Appoligies if this has already recently been asked, but I've done a
google and don't see anything recent on this matter. If so, please
point me to the relevant thread (I am aware of the "please suggest
working solution" thread).

Anyways, after that preamble:
I've been using a DSE router in Half PPP Bridge mode for awhile, and
it works reasonably well, except every once and awhile the connection
"drops"[1].

So I've started thinking about an internal ADSL card for my server box
here. I am aware previously there were numerous problems with internal
cards, ranging from lack of stablitity in the actual connection to
buggy and problematic drivers for Linux.

I now wonder if this has changed much? Are there internal ADSL cards
out on the market today that a) provide good quality connections and
b) have good (preferably open source, or at least supported) Linux
drivers?


[1] Regarding the "drops" on the DSE with half ppp bridge.
The problem appears to be half and half a fault with the linux setup
and with the router. The DHCP client rejects some dhcp replies that
the router gives back (wrong xid code). But the router doesn't respond
to DHCP requests all the time. There appears to be some kind of
internal timeout in the router.

It also seems to do a ARP whohas <realip> before allocating, which is
fine and all, but for some reason, linux replies that it has it, even
when it doesn't (to do with the IPv6 tunnels I believe).

In my not some humble opinion; the router should be programed so that
when its in half ppp bridge, it gives out DHCP responses for ANY and
all requests, since 99.999% of users who use it in this mode plug
directly into the router, so the "right" machine will be the only one
sending requests out.

[Sascha Beaumont]

Post by Nick Clifford
I've been using a DSE router in Half PPP Bridge mode for awhile, and
it works reasonably well, except every once and awhile the connection
"drops"[1].
So I've started thinking about an internal ADSL card for my server box
here. I am aware previously there were numerous problems with internal
cards, ranging from lack of stablitity in the actual connection to
buggy and problematic drivers for Linux.

The biggest problem is the lack of open sourcing for PCI or USB modems,
this leads to drivers being released for specific kernels or
distributions and not being kept updated as things progress and the
modem is no longer in production.

DSE XH1148 usb adsl modem supports Mandrake 9.2, RedHat 9.0 and Fedora
Core 1.

Do you need to run your router in half bridge? Will DMZ suffice? Have
you considered an external modem/router that supports PPTP?

Is the connection dropping a problem with your line maybe rather than
the router? When I used to run in half bridge I'd get a 192.168.1.3
address if the router wasn't on the net - could this be causing problems
for your firewall setup if you've got an internal network also on
192.168.1/24?

Post by Nick Clifford
In my not some humble opinion; the router should be programed so that
when its in half ppp bridge, it gives out DHCP responses for ANY and
all requests, since 99.999% of users who use it in this mode plug
directly into the router, so the "right" machine will be the only one
sending requests out.

What 99% of users *intend* to do, may not be what they do.

Problem is if you've got a combo switch/router that won't always be the
case. There may be some machine that *shouldn't* send out a DHCP request
that does.

Its still got to conform to the DHCP protocol, or else its a bung piece
of equipment and will cause problems down the line. Standards should be
followed. Issue is, when its running in half-bridge with DHCP its got a
address pool of only 1 ip - should it release the DHCP lease? See if the
currently leasing machine is still around, if not then release? Or wait
for the lease to timeout?

I had two machines, both plugged into a DSE router running in half
bridge mode, the router did give DHCP responses to *any* and *all*
machines, unfortunately when both machines were using DHCP this meant
they were playing IP tag.

Sascha