Speed Drop on Lease Renewal

notadoc · 06-18-2015, 02:24 PM

I live in a building with dinner-plate size Cisco hot spots along the corridor ceiling. My first connection seems to be to the closest hot spot, and it's fast. When the lease times out and is renewed, it is to a more distant hot spot (iwconfig shows a different hardware address) and is slow.

How can I force the connection to stay with the first hot spot? Adding this stanza to /etc/dhclient.conf doesn't help:

Code:

lease {
  interface "wlan0";
  renew never;
}

Ideas?

lazydog · 06-19-2015, 01:06 PM

Doesn't matter what you set in your config it matters what is set on the DHCP server when it comes to leases. The DHCP server is set to allow a lease for x amount of time. Halfway thru the lease the DHCP server is going to ask if the lease is still required.

Do you have a way of measuring signal strength? Android has an app called "Wireless Analyzer" that I use all the time. Check the signal strength and see if you are really connecting to what you believe you are connecting to. Then track down the other AP that you roam to. There is nothing stopping someone from setting up a fake AP using the same SSID and running their own DHCP server and capturing all traffic for analysis.

If these AP's are as you say they are then you should not be roaming to another AP unless you have you wireless configured to do so. Also if the signal strength is so weak anything could cause you to lose your wireless connection.

notadoc · 06-19-2015, 01:53 PM

I kinda thought that the DHCP server had a mind of its own on leases.

Signal strength is lower. From iwconfig output:

<Fast> Link Quality=58/70 Signal level=-52 dBm
<Slow> Link Quality=30/70 Signal level=-80 dBm

AFAICT these are legit APs.

One additional observation: When the speed drops (new AP) I can disconnect and then reconnect and reach the fast AP again. Lease time is only 27 min, so this isn't a solution. Sounds like a call to the building network admin is in order.

Thanks for the help.