Norman Ramsey's questions

On a Debian 6.0.6 system (squeeze) I am having trouble resolving a host using Avahi and IPv4. Here is a sample output:

: nr@homedog 10102 ; avahi-browse -a
+   eth0 IPv6 yorkie [00:1f:3b:d8:67:1d]     Workstation          local
+   eth0 IPv6 homedog [bc:5f:f4:5a:b1:73]    Workstation          local
+   eth0 IPv4 homedog [bc:5f:f4:5a:b1:73]    Workstation          local

Notice that homedog, the local machine, is visible both on IPv6 and IPv4. But yorkie, the remote machine, is visible only on IPv4. And avahi-resolve-host-name -4 yorkie.local hangs with no result.

EDIT: The situation is symmetric: yorkie sees itself on IPv4 and IPv6, but it sees homedog on IPv6 only.

On yorkie, the output from iptables -vnL is

Chain INPUT (policy ACCEPT 109K packets, 98M bytes)
 pkts bytes target     prot opt in     out     source   destination     

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source   destination  

Chain OUTPUT (policy ACCEPT 108K packets, 94M bytes)
 pkts bytes target     prot opt in     out     source   destination

(To make the display fit StackExchange without wrapping, I have taken a couple of liberties with horizontal space.) The display on homedog is identical except for the numbers: for all three, it displays 0 packets and 0 bytes. (I have no clue how to interpret these outputs, but it may be informative that yorkie's current uptime is 41 days and homedog's current uptime is 6 hours.)

I found a closed ticket at http://avahi.org/ticket/297, which suggests that the problem is some sort of firewall configuration. I am a complete novice in this area, and through web search I have been unable to inform myself about how to use the iptables command to diagnose or repair the problem. I found another ticket as Debian bug 547974, but this bug was closed without explaining how to fix the problem.

The hypothesis is that somehow the service-discovery packet is being blocked—I don't know on which machine. Can anyone say how to discover which machine is blocking the packet and how to reconfigure it so Avahi discovers the IPv4 address?

Because of a show-stopping bug in Debian autofs 4, I just upgraded to autofs5. It is not honoring the timeout option in my auto.master file:

/var/autofs/removable /etc/auto.removable --timeout=2

I use this map for thumb drives and so on; I don't want a general default timeout of 2 seconds.

I did some digging and although the --timeout option worked in autofs 4, and it appears in some examples on the Web, it is not actually sanctioned (or even mentioned) in the documentation for the auto.master file. So I don't feel I can report the problem as a bug.

How can I get autofs5 to timeout after 2 seconds only on designated filesystems?

Update: I am using a Debian-packaged autofs5, version 5.0.4-3.2.

I'm running sudo version 1.7.4 on Debian squeeze. In this version, unlike some older versions, every pty has to be authorized separately with a password and timeout. In older versions, one password was good for any pty during the timeout period. I'd like to persuade sudo to revert to that older behavior, so that I can use a bunch of xterm windows without having to retype my password continually. Does anyone know how to do this?

I'm running gkrellm which shows that some process on my Debian Linux system is writing approx 500KB/s to eth0. I'd like to find out which process it is. I know a little bit about netstat, but it shows a gazillion open TCP connections and I can't seem to make it produce any information about traffic.

Does anybody know how I can get a list of processes that are actually using the eth0 interface so that I can track down the offender?

FOLLOWUP: The Debian Linux distribution contains a nethogs package which solves this problem definitively. Related tools that are not quite on the mark include iftop, netstat, and lsof.

I'm running into trouble mounting an iPod on a newly upgraded Debian Squeeze. I suspect either a protocol has changed or I've tickled a bug, which I don't know where to report.

I'm trying to mount the iPod so that I have permission to read and write it. But my efforts come to nothing:

$ sudo mount -v -t vfat -o uid=32074,gid=6202 /dev/sde2 /mnt
/dev/sde2 on /mnt type vfat (rw,uid=32074,gid=6202)
$ ls -l /mnt
total 80
drwxr-xr-x 2 root root 16384 Jan  1  2000 Calendars
drwxr-xr-x 2 root root 16384 Jan  1  2000 Contacts
drwxr-xr-x 2 root root 16384 Jan  1  2000 Notes
drwxr-xr-x 3 root root 16384 Jun 23  2007 Photos
drwxr-xr-x 6 root root 16384 Jun 19  2007 iPod_Control
$ sudo umount /mnt
$ sudo mount -v -t vfat -o uid=nr,gid=nr /dev/sde2 /mnt     
/dev/sde2 on /mnt type vfat (rw,uid=32074,gid=6202)
$ ls -l /mnt
total 80
drwxr-xr-x 2 root root 16384 Jan  1  2000 Calendars
drwxr-xr-x 2 root root 16384 Jan  1  2000 Contacts
drwxr-xr-x 2 root root 16384 Jan  1  2000 Notes
drwxr-xr-x 3 root root 16384 Jun 23  2007 Photos
drwxr-xr-x 6 root root 16384 Jun 19  2007 iPod_Control

As you see, I've tried both symbolic and numberic IDs, but the files persist in being owned by root (and only writable by root).

The IDs are really mine; I've had the UID since 1993.

$ id
uid=32074(nr) gid=6202(nr) groups=6202(nr),0(root),2(bin),4(adm),...

I've put an strace at http://pastebin.com/Xue2u9FZ, and the mount(2) call looks good:

mount("/dev/sde2", "/mnt", "vfat", MS_MGC_VAL, "uid=32074,gid=6202") = 0

Finally, here's my kernel version from uname -a:

Linux homedog 2.6.32-5-686 #1 SMP Mon Jun 13 04:13:06 UTC 2011 i686 GNU/Linux

Does anyone know if

• I should be doing something different, or
• If there is a workaround, or
• If this is a bug, where it should be reported?

My local CUPS server is confused about the name of the printer I use. It has two names: hpext and hpext@vm-cups. I can never predict which one is going to work, and if I use the wrong one, jobs just sit in its queue indefinitely.

There are no printers listed in /etc/cupsd/cupsd.conf; instead I have the line

BrowsePoll cups.eecs.tufts.edu

This server lists only hpext and not hpext@vm-cups.
I'm thinking that somehow my local server is confused, and if I can delete the printer from its memory, all will be well. But nowhere in the documentation can I find a command to delete a printer, and the DELETE PRINTER button on the stupid web interface has no effect.

What can I do?

Background: I'm a fan of David Allen's Getting Things Done, and that means when an email arrives in my inbox, if I can reply right away, I want to do so and keep my inbox clear. But there's a problem: if I reply immediately, the chances of my getting a reply to the reply go up. So I want to rate-limit my email by putting a delay on some outgoing messages. Delays of an hour, four hours, or even a day would be suitable for my needs.

My question is how best to implement this idea on a Linux system running postfix?

Here are a few observations:

• I can easily put an X-Delay: header in any outgoing message to say that the message should be delayed, and by how much.
• I can easily interpose something between my Mail User Agent and sendmail.
• Email is as close as I get to a mission-critical service. Outgoing mail must be utterly reliable.
• I want to avoid duplicating the reliable queue service that is already in Postfix.
• It appears that Postfix almost has what I want already. There is a facility called header_checks(5) which will inspect headers and take actions, but although there is an action to place mail into the "hold" queue, there is no action to place mail into the "deferred" queue. If I could reliably get an email into the "deferred" queue with a suitable timestamp (i.e., N hours in the future), I think my problem would be solved.

All suggestions are welcome, although I would prefer not to be in the business of patching Postfix...

I want to find out about the Windows XP "shares" on my wife's windows machine by browsing from my Linux machine using Samba. I am relatively clueless about both windows and samba. I tried a basic operation from the command line and got this error:

: nr@homedog 8088 ; smbclient -L sapphire
timeout connecting to 140.247.184.252:445
timeout connecting to 140.247.184.252:139
Connection to sapphire failed (Error NT_STATUS_ACCESS_DENIED)

I've Googled this error message and have determined that a lot of people have similar problems, but I can't find a workaround. I suspect my wife has to grant some sort of access or permission on the Windows side. Any suggestions?

I can't seem to stop aptitude from upgrading all my packages to testing or beyond.

I'm running Debian lenny, and generally I want to stick with packages from lenny unless I explicitly say otherwise. For particular features I may upgrade a particular package to a version from testing or experimental, but in general I want to stick to the lenny versions. In my /etc/apt/apt.conf I have uttered

APT::Default-Release "lenny";

and my /etc/apt/preferences is listed below.

Problem: whenever I hit the U key in aptitude, it wants to upgrade all my packages at least to testing.

Question: how can I arrange that the U key in aptitude installs only new versions in lenny, not newer versions from testing or elsewhere?

My /etc/apt/preferences (where I freely admit I don't know what I'm doing) is

Package: *
Pin: release a=stable
Pin-Priority: 900

Package: *
Pin: release a=testing
Pin-Priority: 90

Package: *
Pin: release a=experimental
Pin-Priority: 89

Package: *
Pin: release a=gutsy
Pin-Priority: 88

Package: *
Pin: release a=unstable
Pin-Priority: 50

I run several Linux machines at home and at work. Most of my computing is I/O-limited, e.g., large compiler regression suites and the like. At home I also have one machine that captures high-definition video from a terrestrial antenna. One sporting event goes into a single file of about 30GB; I have over 4TB of storage devoted to HD video.

My question is under what circumstances should I stripe? My current setup for my home directory and root filesystem is to stripe XFS over two drives using LVM. Sample output from lvdisplay -m:

Logical extent 0 to 117247:
  Type                striped
  Stripes             2
  Stripe size         64 KB
  Stripe 0:
    Physical volume   /dev/sdb2
    Physical extents  0 to 58623
  Stripe 1:
    Physical volume   /dev/sda2
    Physical extents  0 to 58623

However, I've just read articles with titles like RAID: Not Such a Clever Idea for Your Home PC , Are two drives better than one?, and a piece from storagereview.com—all of which say that striping with RAID-0 is a waste of money and effort for a single-user desktop machine. But

• These studies use Windows, not Linux

• They use hardware RAID, not LVM

• They're not dealing with 30GB video files

I'd like other people's experience on the question for what sorts of configurations, if any, does LVM striping across two disks improve the single-user Linux desktop experience?

I installed Google Desktop for Linux and want to prevent it from running without necessarily deleting all its files. I managed to find and disable the file in /etc/cron.hourly, but gdl_box is still being launched by process 1:

1  5199  5199  5199 ?           -1 Ss   32074   0:01 /opt/google/desktop/bin/gdl_box

I've grepped for gdl in every file under /etc and have turned up no suspects. There doesn't seem to be anything in /etc/init.d or in the /etc/rc*.d directories. How can I find and slay this evil daemon? More exactly, how can I find out what is causing it to be spawned and prevent it from ever spawning in the first place?

I have killed the gdl_box over and over, but without a reboot or an X restart, something in the system keeps respawning it. I would like to find out what and stop it.

EDIT

OK, eventually I replaced gdl_box with a binary that ran ps afwj so I could tell who launched it before it got adopted by init. Imagine my embarrassment when I discovered it was launched from my .profile. I still would love to know a better way to have discovered this, but I've accepted the answer which pointed out the adoption by init (thanks Thomas) which at least stopped me looking under the wrong lamppost.