altavista.com pings ok but refuses answering to Czech academics

[Kevin Darcy]

Ping uses ICMP, DNS uses UDP (or TCP when necessary). To really determine
whether you're being blocked, you'd need to find a UDP service on these
nameservers that responds to you. Unfortunately, best current security
practices involve disabling all unnecessary services, so you're not likely
to find anything.

Why don't you ask Altavista if they're blocking you and if so, why?


- Kevin

Ivan Dolezal wrote:

> Hello,
>
>     I got the following problem: a couple of servers, among them
> Altavista is the most important, are now reachable via ping or IP
> address, but they refuse answering DNS queries for most computers of
> Czech academical network. It is okay for other Czech networks. It looks
> to me like that their hostmasters intentionally blocked us... or where
> is The Truth?
>
> See:
>
> $nslookup
> > server 204.152.190.6
> Default Server:  ns2.alta-vista.net
> Address:  204.152.190.6
>
> > www.altavista.com
> Server:  ns2.alta-vista.net
> Address:  204.152.190.6
>
> *** Request to ns2.alta-vista.net timed-out
>
> $ping 204.152.190.6
> PING 204.152.190.6 (204.152.190.6): 56 data bytes
> 64 bytes from 204.152.190.6: icmp_seq=0 ttl=33 time=179 ms
> 64 bytes from 204.152.190.6: icmp_seq=1 ttl=33 time=179 ms
> 64 bytes from 204.152.190.6: icmp_seq=2 ttl=33 time=179 ms
> 64 bytes from 204.152.190.6: icmp_seq=3 ttl=33 time=178 ms
> 64 bytes from 204.152.190.6: icmp_seq=4 ttl=33 time=179 ms
> 64 bytes from 204.152.190.6: icmp_seq=5 ttl=33 time=179 ms
> 64 bytes from 204.152.190.6: icmp_seq=6 ttl=33 time=178 ms
>
> ----204.152.190.6 PING Statistics----
> 7 packets transmitted, 7 packets received, 0% packet loss
> round-trip (ms)  min/avg/max = 178/178/179 ms
>
>     If anyone has an idea why this is happening, I will greatly
> appreciate your advices.
>
> Thanks in advance, Ivan Dolezal