Why would some channels work and others not?

As some of you may know, most Israelis have a problem going on even-numbered channels, or entering CS and MTS. They lag very badly and often disconnect.

The latest patch changed Kradia's server configuration from the old type of two channels per IP address, to 7. And now those Kradian Israelis who could use only odd-numbered channels are limited to channels 1 and 2.

In other words, while port 8585 works just fine, all other ports lag. Some parts of the day worse than others.
This problem is not unique to a single ISP, all of them have it, although possibly only at higher connection speeds (over 2Mb or so).

Can anyone give me a hint, what to say to my ISP's technical support, to help them get to the bottom of this? They, like Nexon, like to blame everyone but themselves. "It's your router", "It's your firewall", "It's the game host"...

Well, i haven't fixed that yet, but its somethig with the IP your ISP giving to u, maybe nexon is blocking some ip-address range.(this is also the reason why using AOL or any VPN software, u have no lags)
some people saying that port forwarding in the router helped them, u could try it.. though didnt do nothing for me.
some says that "Gamer Box" fixed the issue, but i doubt it, anyway, ill try it soon( u can ask ur ISP to give it a few hours test, to see if it really do anything better)
last thing - who is ur ISP?
mainly, this is Nexon fault, not ISP fault, for sure.
also, im from kradia but i dont thing its server related.....

It's the only protocol assigned port in the range nexon is using;
http://www.speedguide.net/port.php?port=8585

Therefore 8585 may be the only not being traffic shaped by ISPs as assumed P2P traffic.

Thank you, Eos, that sounds very plausible.