Can't access Dathorn server/sites from some dialup IP-s
I am hosting sites at Dathorn for almost a year and I am very satisfied.But several days ago my sites were moved from Dathorns first datacanter to The Planet.
And here comes bad stuff for me. When I (and million or so dialup users from my country) connect to the internet and get IP from specific range (83.131.*) all sites (http, email, ftp, etc) on Dathorns ThePlanet servers are unaccessable.
But when internet connection have IP from some other IP range, sites and everything else works normally.
It is not (?) a dns problem, because it is impossible to access sites in this form:
http://dathorn-theplanet-ip/~username/
and not only sites, but also the WHM is not accessable (https://dathorn-server-host:2087/ or https://dathorn-server-ip:2087/)
When my ISP received that new range of IP addresses in December 2003, I had the same problem at Dathorn, but it was corrected when Andrew removed that IP from his firewall blacklist.
But now he doesn't have these IPs blacklisted, and he talked with The Planet staff and they told him that The Planet doesn't block IPs or similiar which would prevent access (I have sites at The Planet with other webhost provider and there don't have such problem).
I would be very happy if somebody has a clue or knows what might cause this problem?
Thank you very much!