From: ubuntu-uk-boun...@lists.ubuntu.com [mailto:ubuntu-uk-boun...@lists.ubuntu.com] On Behalf Of John Matthews Sent: 15 April 2010 13:50 To: UK Ubuntu Talk Subject: Re: [ubuntu-uk] Firefox wont open up since yesterdays nightly update
Ok, I reinstalled the restricted packages, still the same. As far as proxy settings, not sure what you mean there? I dont have a firewall in Ubuntu, the nearest to a proxy setting I can think of could be my router, but would that have a problem with an ubuntu update? The lack of firewall in Ubuntu does kind of worry me a bit. Tried to install one, but it got too complicated. ------------- Just to pick up on this bit, I feel like giving an explanation on firewalls and network-level protection in Ubuntu :) The networking part of Ubuntu (contained in the kernel) will respond to things called ICMP pings. Pings are a simple way to tell if a computer is there or not. Generally firewalls will stop the computer responding to these pings, depending on the configuration of the firewall. Also, the networking part of the kernel will control how programs 'listen' on ports. A program or service will bind to a port where it can be contacted - these are generally server type programs such as the Apache web server, OpenSSH secure console etc. By default Ubuntu comes with none of these enabled so if a remote user / attacker tried to access any of these on your machine they would get a connection refused from the kernel as there is nothing listening on a specific port. Firewalls seek to increase the security of this behaviour by instead of responding with a connection refused, they silently drop the request and never respond, making it so that the remote user / attacker never knows if there is a computer there or not. Obviously this is safer, but it isn't always desired behaviour. Finally something to note is that if you have any type of ADSL / broadband router at home it will almost certainly have a NAT firewall built in. The firewall can be an explicit firewall or the firewall can be implied due to that fact that a remote attacker can't see anything behind your router. There's lots more to all of this and this is a very simplified view of things but essentially, with Ubuntu, you're pretty safe without a firewall. If you want to go ultra-safe then it can help. Hope this makes sense. -- ubuntu-uk@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-uk https://wiki.ubuntu.com/UKTeam/
