Yet Another Linux Blog

I came across this utility when I was looking to find out how to check what wireless channel I’m using on this Macbook. original post on osxdaily.com

sudo ln -s /System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport /usr/sbin/airport

Here’s what I see at my current location! Do an -h to see more options.

acbook:~ chekh$ sudo airport -s
SSID BSSID RSSI CHANNEL SECURITY (auth/unicast/group)
linksys 00:18:f8:1b:26:86 -61 6 NONE
OCEANA 00:21:29:c5:bc:3f -84 1 WPA(PSK/TKIP/TKIP)
NETGEAR 00:1b:2f:ff:c9:78 -92 1 NONE
love 00:18:39:97:87:2d -82 1 WPA(PSK/TKIP/TKIP)
7B 00:1e:e5:70:87:fb -59 6 WPA(PSK/AES,TKIP/TKIP) WPA2(PSK/AES,TKIP/TKIP)
07FX09012458 00:12:0e:8b:84:86 -86 6 WEP
AwesomeNet 00:1c:10:90:03:2a -94 6 WPA(PSK/TKIP/TKIP)
green 00:1a:70:80:87:a9 -89 6 WPA(PSK/TKIP/TKIP)
linksys_SES_42059 00:1a:70:4d:eb:5f -96 6 WPA(PSK/TKIP/TKIP)
08FX05004778 00:18:3a:aa:17:c2 -95 6 WEP
Malik 00:1e:e5:b1:df:91 -87 6 NONE
08FX04057630 00:18:3a:a7:7b:07 -95 6 WEP
VASYA 00:0f:b5:69:6f:70 -83 11 WPA(PSK/TKIP/TKIP)
lion 00:17:3f:9f:8b:52 -84 11 WEP
OUTPOST 00:14:6c:f5:d7:36 -82 11 NONE
dlink 00:21:91:08:18:75 -85 4 WPA(PSK/TKIP,AES/TKIP) WPA2(PSK/TKIP,AES/TKIP)
Bronstein 00:18:39:f5:cc:85 -90 8 WPA(PSK/TKIP/TKIP)
FINE 00:13:10:c9:ae:02 -86 10 WEP
macbook:~ chekh$ sudo airport -I
agrCtlRSSI: -60
agrExtRSSI: 0
agrCtlNoise: -99
agrExtNoise: 0
state: running
op mode: station
lastTxRate: 54
maxRate: 54
lastAssocStatus: 0
802.11 auth: open
link auth: unknown
BSSID: 0:18:f8:1b:26:86
SSID: linksys
MCS: -1
channel: 6


Law prof and cop agree: never ever ever ever ever ever ever talk to the cops about a crime, even if you’re innocent: http://boingboing.net/2008/07/28/law-prof-and-cop-agr.html

Upgrading to Sun Grid Engine 6.2 - Keeping the old cluster: https://slx.sun.com/1179271114

IP Visualiser: http://it.slashdot.org/comments.pl?sid=1069911&cid=26197769


alex@asdf:~$ ping google.com
PING google.com (74.125.45.100) 56(84) bytes of data.
64 bytes from yx-in-f100.google.com (74.125.45.100): icmp_seq=2 ttl=242 time=1035 ms
64 bytes from yx-in-f100.google.com (74.125.45.100): icmp_seq=5 ttl=242 time=190 ms
64 bytes from yx-in-f100.google.com (74.125.45.100): icmp_seq=6 ttl=242 time=49.4 ms
64 bytes from yx-in-f100.google.com (74.125.45.100): icmp_seq=8 ttl=242 time=56.6 ms
^C64 bytes from yx-in-f100.google.com (74.125.45.100): icmp_seq=9 ttl=242 time=93.0 ms

--- google.com ping statistics ---
9 packets transmitted, 5 received, 44% packet loss, time 8045ms
rtt min/avg/max/mdev = 49.418/284.939/1035.372/378.558 ms, pipe 2


Modern Linux distros like Ubuntu 8.10 or EL5.2 already have all the necessary multicast stuff turned on by default. However, a common diagnostic is to do a “ping -c 2 224.0.0.1″. Every machine on your network that has multicast enabled should respond to that multicast ping. However, both Ubuntu and RH by default enable /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts, so you have to set that to 0 before your machine will respond to that ping. Simply edit your /etc/sysctl.conf and do ’sysctl -p’ and you’re off:

alex@asdf:~$ ping 224.0.0.1
PING 224.0.0.1 (224.0.0.1) 56(84) bytes of data.
64 bytes from 192.168.1.2: icmp_seq=1 ttl=64 time=0.109 ms
64 bytes from 192.168.1.7: icmp_seq=1 ttl=64 time=0.246 ms (DUP!)
64 bytes from 192.168.1.1: icmp_seq=1 ttl=64 time=2.81 ms (DUP!)
64 bytes from 192.168.1.4: icmp_seq=1 ttl=64 time=11.3 ms (DUP!)
64 bytes from 192.168.1.2: icmp_seq=2 ttl=64 time=0.088 ms
64 bytes from 192.168.1.7: icmp_seq=2 ttl=64 time=0.197 ms (DUP!)
64 bytes from 192.168.1.1: icmp_seq=2 ttl=64 time=4.34 ms (DUP!)
64 bytes from 192.168.1.4: icmp_seq=2 ttl=64 time=34.6 ms (DUP!)
^C
--- 224.0.0.1 ping statistics ---
2 packets transmitted, 2 received, +6 duplicates, 0% packet loss, time 1004ms
rtt min/avg/max/mdev = 0.088/6.729/34.647/11.151 ms