Re: [cobalt-users] [RaQ3] Any known problems connecting via ADSL?

[Christopher Jay Manders <Chris.Manders@xxxxxxxxxxxxxxxx>]

Hi,

Might this chap not have a reverse-lookup-able IP address via DNS? I have seen
situations in which many FTP servers come by default to not allow connections
from IP addresses that do not have a PTR record for their IP. I set mine up
that way, regardless, as does FTP.UU.NET and other big ISPs. Furthermore, I
have seen many ISPs that do not correctly allocate reverse DNS PTR records,
especially on businesses, as they assume (correctly) that the client will want
particular names to resolve for a particular IP that services and/or protocols
rely on. Running your own DNS server, for instance, only will work if the
forwards AND reverse DNS maps are the same (at least the DNS servers I have had
to deal with). Or, if the IP is given by a DHCP server that is running NT and
the other side is something else, then the WINS/DNS update for the PTR record
may not work correctly, or show deviant information than what was supplied by
one direction of the DNS resolution. Those could easily cause such inability to
connect to certain services.

Basically, this raises more questions:
-Is the IP reverse DNS lookup-able?
-Does it match the forwards map (www.yahoo.com -> 11.22.33.44, 11.22.33.44 ->
www.yahoo.com)?
-Can the chap 'ping' the RaQ3 from his DSL?
-Using a terminal (like maybe DOS if in Windows), type manually 'ftp
ftp.you.com' and have him send the exact response by the server (most GUI apps
hide [or make their own error message] for the real reasons for failure). What
happens?
-What errors are left in your log files from his IP on your RaQ3?

Just some thoughts. I hope they help narrow it down. Also, I could be wrong.
:-)

Cheers!

Christopher

Per M Knutsen wrote:

> I have a client who persistently fails to connect to one of our RaQ3
> appliance servers via ADSL. His regular modem works just fine. Initially I
> thought maybe his ISP was responsible, but now my client claims that he can
> connect via FTP to other servers via his ADSL connection.
>
> Are there any known issues with ADSL and RaQs (or any other RedHat server)
> running ProFTP?
>
> Per M Knutsen
> http://nethut.no/~pknutsen
>
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