[MUD-Dev] UDP vs TCP/IP

[J C Lawrence]

On Sat, 23 Jun 2001 08:30:37 +0200 
Ola Fosheim <=?iso-8859-1?Q?Gr=F8stad?= <olag at ifi.uio.no>> wrote:

> J C Lawrence wrote:
>> You can also build protocol stacks that dynamically shift between
>> UDP and TCP as the packet loss rates vary.

> Which is even necessary if you want players that sit behind an UDP
> blocking firewall... (The students here seem to be behind one)

Filtering of all UDP is unusual to near the point of non-existance.
Instead UDP and firewalls tends to break in a few simple areas:

  1) UDP provides a three-tupe for packet tracking where-as TCP
  provides a five-tupe.  This makes TCP much easier to process
  properly through a NAT firewall (and actually through firewalls in
  general).

  2) Users of UDP for some reason seem to liek opening UDP
  connections from the server to the client.  Without a custom
  algorithm on the firewall, this won't work.  

  3) UDP is marginally easy to manufacture spoof and has become
  somewhat popular with DDoS kids for bandwidth congestion.  ICMP is
  more popular (by several orders of magnitude,but is also trivially
  filtered UDP is growing here.

Port 53 (DNS) is almost always open for UDP...

--
J C Lawrence                                             claw at kanga.nu
---------(*)                                http://www.kanga.nu/~claw/
I never claimed to be human.
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