I started seeing repeated delivery failure messages from the Linux Kernel Mailing list: permalink
postfix/cleanup: 2819B22313: info: header Subject: Do You Need A Hand? from vger.kernel.org[188.8.131.52]; opendkim: too much header dataA quick Google suggested that this was because the header size was greater than the default of 65536 that OpenDKIM accepts. I tried increasing this to 262144, but this didn't help. I then set
On-Security acceptin opendkim.conf. This caused the mail to be accepted. I then had a look inside the mail:
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sego.es; s=default; <snip> $ grep DKIM-Signature msg.5SAz | wc -l 1000 $ sed -n '1,/^$/p' msg.6SAz | wc -c 396117What on earth are sego.es playing at?
If postfix isn't delivering mail and you have this message in your log file permalink
amavis: (!!)TROUBLE in pre_loop_hook: config: no rules were found! Do you need to run 'sa-update'?check the permissions on subdirectories under
/var/lib/spamassassin/3.004001/If root has a restrictive umask of 0077, then files need to be set world readable
chmod -R a+rX /var/lib/spamassassin/3.004001/
"Opening '/proc/net/rpc/nfs4.nametoid/channel' failed: errno 2" permalink
If you get the above error, make sure that you have CONFIG_NFSD_V4 enabled in your kernel config.
How to load the co-ordinates of caves into OsmAnd permalink
OsmAnd is a free map app for Android.
To overlay the co-ordinates of caves:
* Use the Chrome browser
* visit http://www1.maths.leeds.ac.uk/~read/scuba/gps.html
* scroll down, then long click on a link to a GPX file.
* save to the Downloads directory
* In OsmAnd, tap on the three bars at the bottom left to open the menu
* "My places", "My Tracks", "Import"
* Tap on the icon for a file, it changes to a tick, then "Open"
* for subsequent imports, click on the "+" at the bottom left.
* Finally, on the "My tracks" page, tap on the three dots to the right of a file and "show on map".
After seeing Greg K-H's comments permalink
about old Long Term Support kernels, I updated a couple of servers from 4.4 to 4.14. I ran into a problem with named (BIND) failing to start.
kernel: mmap: named (6332): VmData 35500032 exceed data ulimit 2097152. Update limits or use boot option ignore_rlimit_data.It seems that having the line
datasize 2M;in named.conf is the cause. Just remove that line. It seems that it's commonly been copied for donkeys' years: I can first find it in a config from September 2003.
With systemd 235, playing "Black Mesa" in a systemd-nspawn container stopper working: permalink
Running glxinfo gave the error
libGL error: failed to open drm device: Operation not permittedand strace showed:
open("/dev/dri/card0", O_RDWR|O_LARGEFILE|O_CLOEXEC) = -1 EPERM (Operation not permitted)The fix is to add
--property='DeviceAllow=/dev/dri/card0 rw'to the systemd-nspawn command line
Solved: pcap errors permalink
# iftop -i eth0 interface: eth0 pcap_open_live(eth0): eth0: socket: Address family not supported by protocol # dmesg | tail [595841.213279] iftop uses obsolete (PF_INET,SOCK_PACKET)Make sure that CONFIG_PACKET and CONFIG_PACKET_DIAG are enabled in your kernel config
$ diff .config.old .config 3c3 < # Linux/x86 4.4.70 Kernel Configuration --- > # Linux/x86 4.4.89 Kernel Configuration 635c635,636 < # CONFIG_PACKET is not set --- > CONFIG_PACKET=m > CONFIG_PACKET_DIAG=m $
umount: /mnt/tmp: device is busy permalink
If you are trying to unmount a device, you get the error "device is busy", but lsof/fuser don't show any process holding the device open, it could be that a file on the device is associated with a loop device.
# losetup -a /dev/loop/0: :25280514 (image) offset=55273881600 # losetup -d /dev/loop0 # umount /mnt/tmp(updated, 2016-11-01)
dmsetup info | grep loop dmsetup remove loop0p2 dmsetup remove loop0p3may help too
More hints on unmounting a filesystem: permalink
# ls -l /dev/mapper/ # dmsetup ls # dmsetup info loop0p2 # dmsetup remove loop0p2 # losetup -a # losetup -d loop0 # umount /mnt/tmp
Windows Security Applications (2007-12) permalink
(updated for Malwarebytes, 2016-02-04) When working with friend's PCs, here are some applications I install:
- Secunia PSI Personal Software Inspector (updated 2018-03-14 - this will soon be discontinued)
- (Added 2013-03-04) Filehippo Update Checker
Colleagues also recommend Ninite
reviewed at The Register
- Grisoft AVG free anti-virus
Lavasoft Ad-AwareNot any more - see this article (2011-11-13)
- (added 2008-02-10) And one more link: Windows Sysinternals
- (Added 2011-12-27) SANS ISC recommend MalwareBytes free anti-virus, OTOH: security issues,
- (Added 2013-03-04) The UK government's advice
Hints on running a well-configured outgoing mail server. permalink
If you do not have a static IP address, use your ISP's
mail relay (smarthost).
Make sure that there is a reverse DNS (PTR) record for your
IP address. Make sure that it is not generic (e.g. wylie.me.uk,
rather than client-12-34-56-78.adsl.example.org). You will need
to contact your ISP to do this. (See RFC1912 section 2.1)
Make sure that doing a PTR lookup, then doing an A lookup on that domain name gives the original IP address, e.g.
$ host 184.108.40.206 220.127.116.11.in-addr.arpa domain name pointer wylie.me.uk. $ host wylie.me.uk wylie.me.uk has address 18.104.22.168
Get your ISP to SWIP your IP allocation, so that a whois lookup shows
that it is allocated to you.
Make sure that your ISP has not listed your IP address as dynamic with
any DNSBL, e.g. dul.dnsbl.sorbs.net. If necessary, get your ISP to contact
the DNSBL maintainers and ask for your IP address to be delisted.
- Make sure that your HELO/EHLO string is a FQDN (Fully Qualified Domain Name), e.g. "wylie.me.uk", rather than "NTSERVER", as required by RFC 2821 section 22.214.171.124
Spamhaus reverse DNS
Spamhaus Dynamic IP lists
Yahoo mail help
AOL Technical Standards for E-mail Delivery
AOL Reverse DNS
Messaging Anti-Abuse Working Group Sender Best Communications Practices
If you get errors trying to nfsmount your root partition during a PXE boot permalink
VFS: Unable to mount root fs via NFS, trying floppy. VFS: Cannot open root device "nfs" or unknown-block(2,0): error -6 Please append a correct "root=" boot option; here are the available partitions: Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(2,0)try adding "nfsvers=3" to your kernel command line
LABEL alan KERNEL alan/bzImage APPEND root=/dev/nfs nfsroot=192.168.21.1:/work/netboot/alan/nfsroot,nfsvers=3 \ ip=dhcp nfsrootdebug vga=0x323 firstname.lastname@example.org/,@192.168.21.2/
Gentoo, bash, xmalloc errors permalink
In Gentoo, after turning on the bash use-flag "mem-scramble", I got emerge errors for icu and nmap:
bash: xmalloc: shell.c:1596: cannot allocate 10 bytes (0 bytes allocated)
Just to try and g**gleb*mb it: permalink
Link to a friend's NHS Anti Smoking Campaign
About me: permalink
I'm a computer hacker (in the original meaning of the word), a caver, a fell-walker, and cyclist.
mail me at email@example.com
Note that sending unsolicited marketing e-mail to an individual in the UK is an offence under the Privacy and Electronic Communications (EC Directive) Regulations 2003 and that the collection and processing of personal information is regulated by the Data Protection Act.
Contact Me permalink
Please note that sending unsolicited marketing e-mail to an individual in the UK is an offence under Section 22 of the Privacy and Electronic Communications (EC Directive) Regulations 2003 http://www.legislation.gov.uk/uksi/2003/2426/regulation/22/made
If you are having difficulty e-mailing me, perhaps because of my anti-spam defenses, use this form (See also Hints on running a well-configured outgoing mail server )
Xmas links permalink
UWFRA SARDA BPC Gaping Gill Titan Titan Titan Titan
Captain Brown's Experience on board the barque Robert Hine permalink
My brother David has scanned in and OCR'd a pamphlet my Great^2 Grandfather published entitled Captain Brown's Experience on board the barque Robert Hine
Found, at the summit of Puig des Tossals Verts, Mallorca, on Wednesday 9th November 2011. permalink
A Panasonic Lumix DMC-TZ18 Camera
Contact me for the contents of the SD card and the return of the camera.
Lateral Cleft, Jingling Pot permalink