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Running a UDP Remote Console with Linux 2.6

Posted by simoniker on from the so-there dept.

Bruce Perens writes "Many system admins have learned how to use syslog to log events of remote systems. But when the kernel crashes, its final messages never get to syslog. If you don't have a remote console manager, you won't see them, unless you run netconsole."

4 of 39 comments (clear)

  1. Re:some conditions.. by Bruce+Perens · · Score: 2, Interesting
    Yes. I really want a console server. I can't get one without paying a lot more or getting less for what I'm paying.

    Bruce

    --
    Bruce Perens.
  2. For FreeBSDers, try ethercons by drdink · · Score: 4, Interesting

    If you use FreeBSD and find this interesting, you should take a look at rwatson's ethercons patches. Basically, it is this but supports bidirectional communication. That means you can run a getty on it and login over ethernet console. Rather slick.

    --
    Beware, Nugget is watching... See?
  3. Re:Tempting... by hattmoward · · Score: 4, Interesting

    It may not be as surprising when you note that sysklogd was written in a time where the network was considered more trustworthy, though there is another reason, which is mentioned below. You should also find the syslog-ng package available on your Debian system, which can filter by sending host, although it will spend more CPU time to do the blocking at that level. Both solutions work, though.

    The reason you don't see this feature made more prominent is that UDP packets are easily spoofed, since there is no handshake required to get the payload through. With TCP, someone has to be at the "sending" host to reply to the handshake, while UDP simply accepts what it receives in the single packet (barring the sender being a local-net host, with strict ARP checking on the receiver). So anyway, filtering hosts doesn't completely cover you from log spoofing or DOSing, but it's still a good idea.

  4. Re:Tempting... by Bruce+Perens · · Score: 2, Interesting
    That's a good answer, thanks! I had not thought about the ease of spoofing a UDP packet. I'm actually surprised that so far I am not losing any of them between Texas and California.

    If I had another machine in the same data center, I'd not be sending UDP over the internet.

    Thanks

    Bruce

    --
    Bruce Perens.