Linux, programming and more
Since Debian 6 (squeeze) this is the working method to disable permanent IPv6 implementation. This method is also reboot safe.
cat /etc/sysctl.d/disable-ipv6.conf net.ipv6.conf.all.disable_ipv6=1 |
If you have no possibility to restart your system yet, this change can be made immediately work by executing:
sysctl -p /etc/sysctl.d/disable-ipv6.conf |
Anothe method – perfect for firewall scripts:
echo 1 > /proc/sys/net/ipv6/conf/all/disable_ipv6 |
On June 8, 2011 was world IPv6 day and I shared some VPS boxes. Only one guy wants Ubuntu 11.04 – no problem he get it.
I was painfully remembered that Ubuntu.com has still some problems with AAAA record for security.ubuntu.com… They have no records:) [Read more…]
Manual Allocation: The administrator assigns a pre-allocated IP address to the client and DHCP only communicates the IP address to the device.
Automatic Allocation: DHCP automatically assigns a static IP address permanently to a device, selecting it from a pool of available addresses. There is no lease and the address is permanently assigned to a device.
Dynamic Allocation: DHCP automatically dynamically assigns, or leases, an IP address from a pool of addresses for a limited period of time chosen by the server, or until the client tells the DHCP server that it no longer needs the address.
1 2 3 4 5 6 7 | R1(config)# ip dhcp exclude-address 192.168.10.1 192.168.10.9 R1(config)# ip dhcp exclude-address 192.168.10.254 R1(config)# ip dhcp pool LAN-POOL-1 R1(dhcp-config)# network 192.168.10.0 255.255.255.0 R1(dhcp-config)# default router 192.168.10.1 R1(dhcp-config)# domain-name span.com R1(dhcp-config)# end |
Configure DHCP address:
1 2 3 | Eagle(config)# interface fa0/0 Eagle(config-if)# ip address dhcp Eagle(config-if)# no shut |
Configure DHCP relay:
1 2 3 4 | R1# config t R1(config)# interface Fa0/0 R1(config-if)# ip helper-address 192.168.11.5 R1(config-if)# end |
Configure Static NAT
1 | R2(config)#ip nat inside source static 192.168.20.254 209.165.202.131 |
Configure Dynamic NAT Overload
1 2 3 4 5 6 7 8 9 10 | R2(config)#ip nat pool R2POOL 209.165.202.128 209.165.202.130 netmask 255.255.255.252 R2(config)#ip nat inside source list R2NAT pool R2POOL overload R2(config)#interface Serial 0/1/0 R2(config-if)#ip nat outside R2(config)#interface fastEthernet 0/0 R2(config-if)#ip nat inside # optional ISP(config)#ip route 209.165.202.128 255.255.255.224 serial0/0/0 |
IPV6 Dual Stack Configuration:
1 2 3 4 5 | conf t pv6 unicast-routing interface ethernet0 ip address 192.168.99.1 255.255.255.0 ipv6 address 2001:470:1f0b:1514::7/64 |
IPV6 Routing:
1 2 3 4 5 | Router(config)# ipv6 unicast-routing Router(config-if)# ipv6 address ipv6prefix/prefix-length eui-64 DNS Resolver: ip name-server 2001:470:1f0b:1514::1 |
The standard ftp command/client does not support IPv6 resolution.
A very powerful IPv6 ftp client alternative is lftp.
1 2 3 | id@acer:~$ lftp ipv6.idrobot.net lftp ipv6.idrobot.net:~> dir -rw-r--r-- 1 ftp ftp 0 Aug 26 17:28 test.txt |
And of course Firefox does FTP over IPv6:
ftp://ipv6.idrobot.net OR ftp://[2a01:4f8:131:51e2::10]
In this how to I describe the basically configuration and administration of Postfix on Debian Lenny.
Current I’m using Postfix version 2.5.5
This tutorial should working with older and newer versions.
1 2 | postconf -d | grep "mail_version =" | cut -d" " -f 3 2.5.5 |
You can find the postfix main configuration file under “/etc/postfix”
Let see what wee need to configure a working Internet Mail-Server
1 | postfix ~ # vim /etc/postfix/main.cf |
My example configuration:
1 2 3 4 5 6 7 8 9 10 11 12 13 | myhostname = ipv6.postfix.idrobot.net alias_maps = hash:/etc/aliases alias_database = hash:/etc/aliases mydestination = ipv6.postfix.idrobot.net, localhost.localdomain, localhost mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 smtp_bind_address6 = 2a01:4f8:101:265::37 mailbox_command = mailbox_size_limit = 0 recipient_delimiter = + inet_interfaces = all inet_protocols = all home_mailbox = Maildir/ bounce_template_file = /etc/postfix/bounce.cf |
If you want to relay your mails to another mail-server you can use the relayhost option:
Edit main.cf, and add this line:
1 | relayhost = ipv6.mx.idrobot.net |
Some administration commands:
Show running config:
1 | postconf -n |
Show the default postfix config instead of running one:
1 | postconf -d |
Show message content:
1 | postcat -q 7FB942082 |
Delete all mail in queue:
1 | postsuper -d ALL |
Schedule immediate delivery:
1 | postqueue -i 7FB942082 |
Flush the queue:
1 | postqueue -f |