databird
join:2008-05-17
London, ON
4 edits |  Importance of forwarding ports?
So how come if I don't forward the appropriate ports, some things still work, while others don't work at all?
Examples of programs still working:
• bittorrent clients (at peak download rates even)
• FTP clients (iffy... works one moment, and not the next)
Examples of programs not working at all:
• hosting Warcraft III games
• hosting StarCraft games
So what gives?
I'm behind a hardware firewall that I have no access to. Thus, things like uTorrent are not connectable (even though I download at max speed. My upload is definitely castrated though).
• Original question: how come some programs still work and some don't?
• Is port forwarding only necessary for inbound data?
• Does having ports blocked make the data stream any less reliable, in terms of integrity (say for torrents and hash checks)? I would assume not.
• Can a port be used simultaneously by more than one service or application? |
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Cabal
Premium
join:2007-01-21
Boston, MA
2 edits | Forwarding ports (inward) is required in scenarios where someone would be initiating connections to you, such as hosting a game or other Internet service. When you make a connection outward, your firewall tracks the state of it and nothing further is required to maintain the connection (in most cases, simplified). Bittorrent works without forwarding ports *because* many people do forward those ports, allowing you to make a direct connection to them.
FTP is another beast altogether and is just a messy protocol. Issues there could be caused by the server on the far end or your firewall, but most likely aren't port forwarding-related (»www.openbsd.org/faq/pf/ftp.html).
I personally don't forward anything inward through my firewall, and have yet to find a game (PC, PS3, or Wii) or protocol I cannot play/use (but I do not host games, a la StarCraft).
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Would you trust a brain surgeon with two years' experience? |
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rosco
Premium
join:2003-11-10
USA
 ·Verizon Online DSL
| reply to databird
Generally not having ports forwarded will affect inbound connections not making it to you. Some programs can still work in this scenario, and others may not work at all, it really depends on the need for unrequested incoming connections.
I can't say if other hardware firewall options are blocking some outbound ports though.
I am behind a hardware firewall at work, and I can get pretty fast downloads as long as there are a good number of seeds/peers. When downloading torrents, I notice that the peers that respond quickly to my requests usually are able to connect right back to me no problem...maybe the connection is still active through the router from my request, so it makes it back through to me?
I'm no expert but that is what seems to be happening in my situation. |
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GunnarDanne
join:2002-12-02
Crown City, OH
| reply to databird
You live in a house alone. All the mail going to your house is obviously for you so you open it.
You live in a house with multiple people. There is one mailbox. Imagine the mail has no name on it to who it is addressed to. Unless you already sent for something and know what to look for in return, you throw it away because it could be a bad perfume sample.
You live in a house with multiple people. There is a mail slot with each person's name on it and a mailbox for mail with no name on it. Each person will open the mail addressed to them no matter what. Unrecognized mail in that shared box will be thrown away. |
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