Post tagged: network

Askozia Desktop Appliance

So last weekend finally had some time to work with a Askozia Desktop Appliance. It actually arrived much earlier but without a Power Supply. Initially I though, "this is strange; I didn't know this supported PoE". (Power Over Ethernet). It turns out it didn't and there was a shipping mistake. After contacting the vendor, they sent me the required Power Supply. Overall I think the product is quite nice. It has a very nice User Interface that is quite easy to use. Simple configurations are indeed very easy to set-up. My feeling is that, as with any GUI, it usually trades user-friendly with expressiveness. So while I could configure most of the things I wanted from the UI, it did not support my home network topology fully. Initially, I had a DMZ vs Home-LAN configuration, with the Askozia box in the DMZ. Because the separation between the DMZ and the Home-LAN was through the router, it considered all the IP phones (in the Home-LAN) on the other side of the NAT, so things did not work properly. ...

Remote Bridging

Sometimes we need to connect two or more geographically distrubuted ethernet networks to one broadcast domain. There can be two different office networks of some company which uses smb protocol partially based on broadcast network messages. Another example of such situation is computer cafes: a couple of computer cafes can provide to users more convinient environment forr playing multiplayer computer games without dedicated servers. Both sample networks in this article need to have one *nix server for bridging. Our networks can be connected by any possible hardware that provides IP connection between them. Connecting Two Remote Local Networks With Transparent Bridging Technique Short description In described configuration we are connecting two remote LANs to make them appearing as one network with 192.168.1.0/24 address space (however physically, presense of bridges in network configuration is not affecting IP protocol and is fully transparent for it, so you can freely select any address space). Both of the bridging servers has two network interfaces: one (as eth0 in our example) connested to the LAN, and second (eth1) is being used as transport to connect networks. When ethernet tunnel between gateways in both networks will be bringed up we will connect tunnel interfaces with appropriate LAN interfaces with bridge interfaces. Schematically this configuration can be following: +-------+ +-------+ | br0 | | br0 | ...

Native Kerberos Authentication with SSH

This article is about integrating OpenSSH in a kerberos environment. Allthough OpenSSH can provide passwordless logins (through Public/Private keys), it is not a true SSO set-up. This article makes use of Kerberos TGT service to implement a true SSO configuration for OpenSSH. Pre-requisites First off, you'll need to make sure that the OpenSSH server's Kerberos configuration (in /etc/krb5.conf) is correct and works, and that the server's keytab (typically /etc/krb5.keytab) contains an entry for host/fqdn@REALM (case-sensitive). I won't go into details on how this is done again; instead, I'll refer you to any one of the recent Kerberos-related articles (like this one, this one, or even this one). Just be sure that you can issue a kinit -k host/fqdn@REALM and get back a Kerberos ticket without having specify a password. (This tells you that the keytab is working as expected.) ...