Showing posts with label ipv4. Show all posts
Showing posts with label ipv4. Show all posts

Wednesday, July 08, 2015

Running TFTP server on Ubuntu 14.04

# Install tftpd-hpa package
apt-get update
apt-get -y install tftpd-hpa

# Fix config file broken by default
# - use correct tftpboot directory rather than random location under /var
# - chroot to tftpboot
# - allow uploading of files but not overwriting existing
# - listen IPv4 and IPv6 instead of IPv6 only
# - enable logging
mv /etc/default/tftpd-hpa /etc/default/tftpd-hpa.old
cat <<'__EOF__' >/etc/default/tftpd-hpa
TFTP_OPTIONS="--secure --create --listen --verbose"

# Create tftpboot directory and use proper permissions
mkdir /tftpboot
chmod -R 1770 /tftpboot 
chown -R root:tftp /tftpboot

# Restart service
service tftpd-hpa restart

P.S. There's config file bug causing tftpd to listen only IPv6 connections by default...

Saturday, December 13, 2014

Prefer IPv4 over IPv6 on CentOS 6

To prefer IPv4 (A) addresses over IPv6 (AAAA) on CentOS 6 you need to add new file named /etc/gai.conf with following content. Last line is what controls if IPv4 or IPv6 should be tried first.

Wednesday, December 10, 2014

Oddities of dnsmasq when used with IPv6 resolvers

# dnsmasq --version
Dnsmasq version 2.68  Copyright (c) 2000-2013 Simon Kelley
Compile time options: IPv6 GNU-getopt DBus i18n IDN DHCP DHCPv6 no-Lua TFTP conntrack ipset auth

# md5sum dnsmasq*
8a704b6aa977df9485b3faf940cc5e35  dnsmasq_2.68-1_all.deb
60bafb9b863671bb02595505a447270c  dnsmasq-base_2.68-1_amd64.deb

There was odd "[icmp6 sum ok] ICMP6, destination unreachable, unreachable port" going out from my server every time DNS reply was received. Turns out it was because dnsmasq IPv6 support is buggy.