WIndows7 and Echolink UDP Port Sttings

Discussion in 'Echolink/IRLP Tech Board' started by N8RT, Apr 12, 2010.

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  1. AB8ZL

    AB8ZL Ham Member QRZ Page

    Changing the lease time shouldn’t affect anything except how often your computer requests a renewal. A computer will start to ask for a renewed lease from the DHCP service after half of the lease time has expired. The DHCP service will issue the system a new lease on the same IP address when it receives that request. How often this happens should not have any effect on your use of that computer.

    The lease time only counts while the computer is connected to the network, once it disconnects, the lease is terminated. Most DHCP services will give a computer the same IP that it had last time it connected if it is available, but not all. You can’t simulate a static address by playing with lease times.
  2. W7IMM

    W7IMM Ham Member QRZ Page

    OK, that's what I originally thought.

    Doesn't that make it a REAL PIA if one wants to use Echolink on a portable computer and a home network unless you permanently open those ports on your home network globally?

    I don't understand why Echolink must use somewhat obscure or unique ports to work...... I wonder why couldn't they use the same ports as any other VOIP software, like Skype for example?
  3. AB8ZL

    AB8ZL Ham Member QRZ Page

    Echolink runs as a service, Skype is designed to run as a client.

    Any software designed to run as a service will required ports to be forwarded to if it is running behind a NAT router. It isn't a matter of what ports it uses, but a matter of who initiates the connection.

    If the connection is initiated from your computer, your router keeps a table containing all requests and what port they were on. When a packet comes into your router, it checks this table to see where to route the packet too. Echolink is not designed so that your computer initiates the connection, rather it waits for a request from the outside and your router needs to be told where to send that connection as it wont be in the routers table.

    I agree that they should have put more thought into how they designed Echolink as it could have run more like Skype where it will periodically check to see if there is traffic rather then waiting for a request. This is much harder to code then a simple service but it sure makes it easier on the end user.

    There are lots of routers that allow you to configure a static address from the routers DHCP service. You said you were using a Linksys router, you might want to check and see if it can run any aftermarket software like DDWRT that would allow you to configure a static address for your computer on the router.
  4. VA3CSS

    VA3CSS Ham Member QRZ Page

    You've got it all backwards.

    The "Lease Time" is not set at the computer. It's set at the DHCP server (in this case, the router.) How often the computer asks is not the issue, or the problem. The problem was, it was assigned a different IP than the last time, so the Port Forwarding rule lost it's effect as a result.

    Once again, backwards.

    When the computer is connected, the IP is in use. There is no "Lease Time" during this time, because the IP is already in use.

    The "Lease Time" only starts when the computer disconnects. This is because "Lease Time" is defined as the amount of time that a previously-assigned IP address will remain marked as unavailable to other devices asking for an IP.

    Like a lease on an apartment - nobody else can rent that same apartment while you have a valid lease.

    When the lease is up, that IP address is now available to be "reclaimed" by the server, and hence made available for others.
  5. KY5U

    KY5U Premium Subscriber QRZ Page

    All my computers have "names" on the local host. I go into the router firewall and create an application (i call mine "echolink") to open up the echolink ports and assign it to a computer. Regardless the net address assigned to a computer, the port open application sticks to the "name". I leave the router firewall on and turn windows firewall off.

    Echolink works great under XP, Vista, and Windows 7 here.
  6. AB8ZL

    AB8ZL Ham Member QRZ Page

    I’ve been doing this for over 25 years, I have nothing backwards.

    Yes the lease is issued but the DHCP server, but it is issued on request from the client computer. The client will ask for a renewal of its lease after half the lease time expires. Networking 101.

    Huh? Of course there is. The lease is how the DHCP service tracks what IP addresses are in use. An IP address that has no lease is available for the DHCP service to issue to any computer requesting an IP address.

    You couldn’t be more incorrect, the lease time starts when the computer is connected. Most DHCP services, including those on most home routers, will show you the currently connected computers and the time remaining on their leases. If you watch this list for awhile, you will see that the computers that are still connected to the network will always have less than half of their lease time used as they request a renewal at that time). Systems with more than half their lease time showing will be those that have disconnected from the network recently.

    Even better, just run “ipconfig /all” at a command prompt on any computer issued an IP address by the DHCP service and it will show you the time the lease was obtained and when it expires.

    The lease time was never intended to reserve an IP address for a computer that isn’t connected. It is an unintended consequence of the need for the DHCP service to hold Addresses for computers that are connected. Without a lease time, the DHCP service would have to constantly poll every computer to see if the address is still in use. Leases reduce the amount of maintenance network traffic, they aren’t intended to “reserve’ addresses for unconnected computers, that’s what static assignments are for.
  7. W0BTU

    W0BTU Ham Member QRZ Page

    I finally got around to doing this. It worked. Thanks!
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