Cover V11, I09



Questions and Answers

Amy Rich

Q Our mail hub is a FreeBSD 4.5-STABLE box running Postfix. We were recently the target of a large-scale spam attack. There are still a lot of undeliverable bogus messages sitting in the queue (no valid user, and no valid bounce address). I want to remove all of these bogus files, but I'm not certain whether I can actually just rm the files while the mail server is running, or whether I must shut it down and remove the spooled messages with some other program. Any clues?

A Recent versions of Postfix include an option to the postsuper command to clean out queued messages by queue ID. To delete a message with a queue ID of ABCDEF, for example, you would do:

postsuper -d ABCDEF
If you have a large number of messages to remove, create a file with one queue ID per line and then run:

postsuper -d - < file
This is usually safe to do while Postfix is running, but there is a small chance of deleting new incoming mail if it's assigned the same queue ID before the bad message is deleted. From the Postfix FAQ at:
The [possible conflict in message removal] scenario goes like this:

  • The Postfix queue manager deletes the file that postsuper was supposed to delete, because Postfix was finished with the message.
  • New mail arrives, and the new message is given the same queue ID as the message that postsuper was supposed to delete. The probability for reusing a deleted queue ID is about 1 in 2^15 (the number of different microsecond values that the system clock can distinguish).
  • postsuper deletes the new message file, instead of the old file that should have been deleted.
Q I'm having some issues with Jumpstart on Solaris 8. I have a U2 acting as my Jumpstart server, and I've been churning out machines just fine. I tried to do an overhaul of a number of my packages, and now I can't get any of my machines to jumpstart properly, even if I remove the scripts that add the packages. Now when I try to do a jumpstart, it reads the initial profile and creates the base OS image. When it reboots to start the next phase, however, it claims that the hostname I've given the machine is invalid. This same hostname worked just fine in the initial phase of the jumpstart. I've stopped the Jumpstart process and looked at /etc/hosts. Sure enough, even though /etc/hostname.hme0 has the correct hostname, there's no corresponding IP/hostname information in /etc/hosts. All /etc/hosts has is a entry for localhost. What did I do that broke my Jumpstart?

A It sounds as if you've corrupted your Jumpstart boot image. When you were redoing your packages, did you happen to export your Jumpstart boot image read write and then try to jump your machine? If so, you probably overwrote files in the boot image that used to be symbolic links to /tmp during the boot process. To be absolutely sure that you correct all of the corrupted parts of the image, you should recreate your boot image from an original ISO image with the setup_install_server script. If you want to just try to repair your image, the following files in $CDROM_DIR/Solaris_8/Tools/Boot/ should be symbolic links instead of real files:

etc/default/init -> ../../tmp/root/etc/default/init
etc/defaultdomain -> ../tmp/root/etc/defaultdomain
etc/defaultrouter -> ../tmp/root/etc/defaultrouter
etc/ -> ../tmp/root/etc/
etc/ -> ../tmp/root/etc/
etc/format.dat -> ../tmp/root/etc/format.dat
etc/inet/hosts -> ../../tmp/root/etc/inet/hosts
etc/inet/netmasks -> ../../tmp/root/etc/inet/netmasks
etc/instance -> ../tmp/root/etc/instance
etc/krb5/krb5.conf -> ../../tmp/root/etc/krb5/krb5.conf
etc/net/ticlts/hosts -> ../../../tmp/root/etc/net/ticlts/hosts
etc/net/ticots/hosts -> ../../../tmp/root/etc/net/ticots/hosts
etc/net/ticotsord/hosts -> ../../../tmp/root/etc/net/ticotsord/hosts
etc/nodename -> ../tmp/root/etc/nodename
etc/nsswitch.conf -> ../tmp/root/etc/nsswitch.conf
etc/ps_data -> ../tmp/root/etc/ps_data
etc/resolv.conf -> ../tmp/root/etc/resolv.conf
etc/sysidcfg -> ../tmp/root/etc/sysidcfg
etc/transfer_list -> ../tmp/root/etc/transfer_list
etc/vfstab -> ../tmp/root/etc/vfstab
etc/.mnt.lock -> ../tmp/root/etc/.mnt.lock
etc/.name_service_door -> ../tmp/root/etc/.name_service_door
etc/.sysIDtool.state -> ../tmp/root/etc/.sysIDtool.state
var -> ./tmp/root/var/
.tmp_proto/kernel -> ../tmp/root/kernel
Also be sure that etc/path_to_inst contains only the following:

Your Jumpstart may have also created some other extraneous files that you should delete. Use find to locate all of the files that were modified on the date that you tried your last unsuccessful jumpstart. Before you try another jumpstart, be certain that your image is shared read-only, or you'll corrupt the boot image again.

Q I was trying to compile OpenSSH on my OpenBSD machine, but I keep getting the following error:

- -L. -Lopenbsd-compat/  -L/usr/local/lib -R/usr/local/lib -lssh -lopenbsd-compat -lz -lsocket -lnsl  -lcrypto
Undefined                       first referenced
 symbol                             in file
__inet_ntoa                         ./libssh.a(channels.o)
__inet_ntop                         sshconnect.o
ld: fatal: Symbol referencing errors. No output written to ssh
collect2: ld returned 1 exit status
*** Error code 1
I tried manually adding in -lresolv, since it seems like it's missing some resolver functions:

gcc -o ssh ssh.o sshconnect.o sshconnect1.o sshconnect2.o sshtty.o 
  readconf.o clientloop.o -L. -Lopenbsd-compat/ -L/usr/local/lib \
  -R/usr/local/lib -lssh -l openbsd-compat -lz -lsocket -lnsl \
  -lcrypto  -lresolv
Undefined                       first referenced
 symbol                             in file
__inet_ntoa                         ./libssh.a(channels.o)
__inet_ntop                         sshconnect.o
ld: fatal: Symbol referencing errors. No output written to ssh
collect2: ld returned 1 exit status
*** Error code 1
Any clues why it can't find the resolver functions?

A This looks like you have installed your own version of bind, and gcc is picking up the "new" include files first. Try compiling with -lbind, if you have a /usr/local/lib/libbind.a, or try fixing your bind installation so that gcc does not pick up the conflicting include files first.

Q We have a Graphite series Apple Airport that handles the 802.11b bridging at work. The clients are two FreeBSD 4.5-STABLE laptops with Lucent gold cards. The Airport was also upgraded to a gold card, so we could do 128-bit WEP, when it was purchased (before it was discovered that WEP was broken).

We recently moved offices and reinstalled the two laptops. Now, with no discernible pattern, we're seeing very odd behavior on our wireless LAN. Everything will be working just fine, and then the laptops will be unable to talk to anything, including each other and the Airport. The LEDs on the laptop Lucent cards look normal, though, and the lights on the Airport also look normal. The wired LAN can still talk to the Airport when this happens. If we put the laptops into ad hoc mode, they can talk just fine, but they obviously can't talk with the wired network at that point. This also breaks DHCP, which is used to feed the laptops much of their network configuration information, including the IP.

We aren't sure if we accidentally did something to the Airport, the laptop configuration, or what. Any insight you have would be appreciated.

your airport's ethernet address


plaintext WEP key

A Since you made several changes at once, that's going to make it harder to track down the issue:

  • Because the wired side can still talk to the airport, I would guess it's not a physical wiring issue in your new building. If you haven't already done so, you may want to test all of the wires, anyway, for future sanity.
  • Since the laptops can talk to each other in ad hoc mode, it's probably not the gold card in either laptop. It's also unlikely that it's your laptop configuration, since it works some of the time. Just in case, however, I'll go over what should be in your config files.
  • It's unlikely that it's the Airport configuration, since, again, you said it works some of the time. You can redo the Airport configuration to be sure, and you may also want to reset the Airport and upgrade the firmware while you're at it.
  • The wireless card in your Airport could be failing. The best way to test this is to swap cards with a known working card, perhaps from one of the laptops.
  • Your Airport could be failing. There are known hardware issues with certain serial number ranges of Graphite Airports.

Laptop configuration:

The laptop configuration is fairly simple. It can be completely done in /etc/pccard.conf, or you can split it into /etc/pccard.conf and /etc/dhclient-exit-hooks. I prefer the latter solution, because it allows you to move between multiple networks without having to manually reset your configuration. /etc/pccard.conf should have the following entry:

# Lucent WaveLAN/IEEE
card "Lucent Technologies" "WaveLAN/IEEE"
   config  0x1 "wi0" ?
   insert  logger -t pccard:$device -s WaveLAN/IEEE inserted
   insert  /etc/pccard_ether $device
   remove  logger -t pccard:$device -s WaveLAN/IEEE removed
   remove  /sbin/ifconfig $device delete
/etc/dhclient-exit-hooks is the file that will contain all of the customizations such as your WEP key, power save mode, etc. If you keep a WEP key in this file, it should only be readable by root. Here's an example /etc/dhclient-exit-hooks file; replace the following with the proper values for your site:

your airport's ethernet address


plaintext WEP key

#!/bin/sh -x

# Read the BSS ID and network name
        bssid=cmd | awk '$1 == "Current" && $2 == "BSSID:" { print $4 }'
     bssnet=cmd | awk '$1 == "Current" && $2 == "netname" { print $5 }'}

# Try to identify and configure for the wireless net
        if [ "$bssid" = "your airport's ethernet address" ]
                # On the work LAN
                $cmd -e 1
                $cmd -n LANNetworkName
                $cmd -k 'plaintext WEP key'
        elif [ "$bssnet" = "LANNetworkName" ]
                # On the work LAN
                $cmd -e 1
                $cmd -n LANNetworkName
                $cmd -k 'plaintext WEP key'

                # unknown net, turn off encryption
                $cmd -e 0
                $cmd -n ''

# Initialize the WaveLAN card with the proper parameters
if [ "$interface" = "wi0" -a "$reason" = "PREINIT" ]
        cmd="/usr/sbin/wicontrol -i $interface"
        $cmd -P 0 # turn off powersave mode for better throughput
        $cmd -s

        if [ "$bssid" = "44:44:44:44:44:44" ]
                # Unknown, try known networks
                $cmd -e 1
                for net in LANNetworkName
                        $cmd -n $net
                        sleep 1
                        if [ "$bssid" != "44:44:44:44:44:44" ]
exit 0
When you insert the card, it should connect to the network, and you should be able to see the current settings by executing the following command as root:

/usr/sbin/wicontrol -i wi0
If you're having issues making a connection at this point, you can use the LEDs to help diagnose the problem. Look at table B-1 in Appendix B of or the user manual that came with your gold card. If your LEDs are both blinking once every 10 seconds, it means that the card in your laptop is ok, but that it can't establish a connection with the base station.

Airport configuration:

You can configure the Airport from pretty much any kind of machine these days. If you're using a 128-bit WEP key, though, be sure that you find software that supports it. I know people who've had good luck with Windows clients using Freebase ( and some who have used the Java-based configurator v1.5 on UNIX hosts (

If you have a tool that will let you upload new firmware, you may also want to completely reset the Airport (hold in the reset switch within a few seconds of turning on the Airport. The right light should flash amber when the Airport has been reset). Prior to 1.3, Apple's Airport firmware was supplied as a standalone file as part of a software download bundled into a smi archive file. However, with the 1.3 release, the firmware is now embedded within the base station admin utility. It's possible to extract the firmware image using ResEdit, or you can grab a copy from firmware (

Airport failure:

There is a recall on Apple Airport base stations with the serial number range PW940... to PW952... These Airports had a tendency to blow their capacitors, resulting in the constant reset of the station. I've also seen the stations fail slowly with the symptoms you describe. Perhaps your Airport received a power surge that damaged one or more of the capacitors. Take a look at for a list of symptoms, hardware fixes, and information on the recall from Apple.

Q I'm starting to enter the world of writing GUI Perl applications. Are there any good Perl/GUI application development tools out there, preferably something where I can do drag and drop programming?

A Most GUI applications that you're going to write in Perl will probably be integrated with Tk. Take a look at O'Reilly's Mastering Perl/Tk book:
the Perl/Tk Web site:
and the Perl/Tk FAQ:
The User interface section on may also be of some use if you're looking to integrate with something other than Tk:
If you're specifically looking for drag and drop GUI Perl/Tk code builders, take a look at Guido, an open source tool that does drag and drop Perl/Tk development:
Spectcl and related projects may also be worth looking at:
Amy Rich, president of the Boston-based Oceanwave Consulting, Inc. (, has been a UNIX systems administrator for more than five years. She received a BSCS at Worcester Polytechnic Institute, and can be reached at: