Tag: dns

IT

How to generate SSH Fingerprint DNS records

ssh-keygen -f /etc/ssh/ssh_host_rsa_key.pub -r hostname
ssh-keygen -f /etc/ssh/ssh_host_dsa_key.pub -r hostname

You can put the output to your dns zone.

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© GeekLabInfo How to generate SSH Fingerprint DNS records is a post from GeekLab.info. You are free to copy materials from GeekLab.info, but you are required to link back to https://www.geeklab.info

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Linux

DNS and multiple VPNs: Using dnsmasq to access multiple dns suffixes

On my Fedora 15 laptop, I'm almost always connected to several VPNs simultaneously. One VPN to my office or to my home (depending on where I am), one to the data center, one to a customer. These connections all have their own DNS server with their own suffix.

To make all dns suffixes working, I created a script that redirects all outgoing DNS traffic to dnsmasq running on localhost, which in turn forwards all requests for .lan to 192.168.15.254 and all requests for .gl to 192.168.1.254.

The script was put in /etc/NetworkManager/dispatcher.d/10-DNS:

if [ -e /var/run/dnsmasq.localhost ]; then
        cat /proc/`cat /var/run/dnsmasq.localhost`/cmdline |grep dnsmasq >/dev/null 2>/dev/null && \
        kill `cat /var/run/dnsmasq.localhost`
fi
 
if [ "$2" == "up" ]; then
        cp /etc/resolv.conf /etc/resolv.conf.dhcp
        echo nameserver 127.0.0.1 >  /etc/resolv.conf
        echo domain $DHCP4_DOMAIN_NAME >> /etc/resolv.conf 
        echo search $DHCP4_DOMAIN_NAME >> /etc/resolv.conf 
        /usr/sbin/dnsmasq -C /dev/null -r /etc/resolv.conf.dhcp --server=/gl/192.168.1.254 \
            --server=/lan/192.168.15.254 --bind-interfaces --listen-address 127.0.0.1 \ 
            --pid-file=/var/run/dnsmasq.localhost
fi

Once I had to fix resolv.conf manually when I connected my laptop to my Samsung Galaxy SII as well. This may mean I need to improve the script some day, but for the time being, it works good enough.

© GeekLabInfo DNS and multiple VPNs: Using dnsmasq to access multiple dns suffixes is a post from GeekLab.info. You are free to copy materials from GeekLab.info, but you are required to link back to https://www.geeklab.info

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IT

PXEboot with CentOS 5.6 and dnsmasq

Install the required software:
yum install dnsmasq

Open up the firewall:
/sbin/iptables -I INPUT -m udp -p udp --dport 67 -j ACCEPT
/sbin/iptables -I INPUT -m udp -p udp --dport 53 -j ACCEPT

Then run:
dnsmasq -d --interface=br0 --dhcp-range=181.30.68.111,static --dhcp-host=84:2b:2b:78:30:79,181.30.68.112 --dhcp-option=option:router,181.30.68.65 --dhcp-boot=pxelinux.0 --enable-tftp --tftp-root=/var/ftpd

Put all required files, such as pxelinux.0 from the package syslinux in /var/ftpd

Ubuntu/Debian

I'm running RedHat-based software on all of my machines. Above information may be useful for Ubuntu/Debian users, but it's not tested and I'm not supporting it.

Servers: RedHat Enterprise Linux/CentOS is more suitable for servers, as there's a lot of professional level support available. I think that's important, because if I say, get a car accident, I want the servers to be managable by another professional.

Desktops/Laptops: RPM packages are pretty exchangable between RedHat-based platforms. That's a good reason to run Fedora on the desktop.
© GeekLabInfo PXEboot with CentOS 5.6 and dnsmasq is a post from GeekLab.info. You are free to copy materials from GeekLab.info, but you are required to link back to https://www.geeklab.info

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