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visits member for 2 years, 11 months
seen Sep 18 at 21:14

Jun
9
comment Login without running bash_profile or bashrc
This is also true for sftp - even SSH subsystems are apparently executed from within a shell.
Jun
21
comment How does Duplicity check for modifications (mtime or checksum)?
Unfortunately, it's hard to find a proper test case, but I'll try to find one. Thanks for the hint with rsync-options!
Jun
21
comment How does Duplicity check for modifications (mtime or checksum)?
That's impossible - Amazon S3 and even IMAP are storage options for duplicity, and there is no rsync available on either.
Jun
21
comment How does Duplicity check for modifications (mtime or checksum)?
Will that work with duplicity's architecture? There is no "intelligent" rsync at the remote end; does it store the checksums in an index tar archive for that purpose? Or will it have to read the backup files in over the network to determine the checksums of the remote files?
Jun
9
comment Unzipping files that are flying in through a pipe
Nice one-liner, and +1 for mentioning that the file has to fit into memory. (There is unfortunately no way to unzip a pkzip file due to the file format structure).
Jan
31
comment What is the motivation for DNS64?
I see, so a host will always try to contact a remote host by the address family that has been returned by the DNS lookup, but fail if there is no corresponding interface available? Does that also mean that an IPv4-only application (e.g. one with hard-coded IP literals) will never be able to work on an IPv6-only host (at least not without any modifications to the network stack)?
Jan
31
comment What is the motivation for DNS64?
So when an IPv6-only host receives an A reply, it doesn't try to contact the IPv4 address over IPv6 (by encapsulating it into an IPv6 packet, like 0::de:ad:be:ef:0...:0? The gateway could then change the header to IPv4 and do the NAT translation. Wouldn't that be an easy way to implement IPv6 to IPv4 connectivity?
Dec
4
comment /32 subnets on Ethernet via DHCP
I'll do that (guess there's a lot more more to IP addressing than what was explained in my networking class ;). I'm pretty certain about the public IP addresses though; the static /30 is not translated in any way (the webserver on the host is reachable from the internet on that address), and in our campus management system I can clearly see my "personal" public IP address. Incoming connections to port 80 are possible as well. Seems like a giant waste, but they apparently do it to comply to wiretap legislation which would otherwise force them to log all dynamic IP assignments in time.
Dec
4
comment /32 subnets on Ethernet via DHCP
At my old university, I once requested a static IP for a host, and they assigned it a /30 public address like you described. I've always wondered whether there was any more efficient way to handle that (but they don't seem to have a lack of public addresses - every electric door opener has a public IPv4 address...). At my current university, all the users get a static, public IP by default, in a /16 subnet - but I can't see any ARP requests etc. on the network. I was always wondering how the clients know where to send traffic to another host on the same subnet in that environment.
Dec
3
comment /32 subnets on Ethernet via DHCP
I want to be able to use a firewall between all the clients on the local network and especially reduce the amount of broadcast on the segment, while still allowing traffic on certain ports.
Dec
3
comment /32 subnets on Ethernet via DHCP
The drawback would be a potential waste of IP addresses - I'm using private adresses, so in my case it's not a big deal, but how does that work with public addresses? VLANs sound like a nice idea - I'll check if my switch supports them. Would the configuration also be a /30 mask for all the hosts? If not, how do the clients know to send their packets to the gateway instead of using ARP and directly transmitting on the layer 2 interface?
Dec
2
comment /32 subnets on Ethernet via DHCP
Looks like the cleanest solution, but it wastes three addresses. I was hoping for a way to somehow eliminate subnets altogether.
Nov
26
comment huponexit for non-login shells
That doesn't seem to work - the kill doesn't seem to be sent to the child processes in the first place, since the shell isn't a login shell...
Nov
25
comment huponexit for non-login shells
I want the opposite behavior of nohup.
Nov
21
comment Is it possible to run a VNC server without a GPU on linux?
Xvfb seems to be exactly what I was looking for.
Nov
21
comment Is it possible to run a VNC server without a GPU on linux?
There is no machine yet - I'm thinking about building a home server or renting a hosted server, and I'm wondering if I should get one that has a GPU if I want to occasionally use a GUI application on it. It's going to run Linux in any case.
Nov
14
comment UDP and NATs - is the timeout bidirectional?
I'm already sending heartbeats from the server to the client, I'm just not sure if that's enough to keep the mapping in the NAT alive, or if the client has to send something too.
Nov
2
comment Does the TCP source port have to be unique per host?
Thanks, that answers the theoretical part of my question completely! I'll just have to try for every TCP implementation, I guess.
Oct
27
comment Source for 1Gbit Ethernet hub
Oh, I didn't know that. I've always figured that since there are no dedicated wire pairs for sending and transmitting, there is no way to detect collisions. I edited my answer accordingly.