Linux Firewalls Post: 7766

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Top Forums UNIX for Advanced & Expert Users Linux Firewalls Post 7766 by loadc on Monday 1st of October 2001 10:54:46 PM

10-01-2001

Registered User

Just a note...

If you have some time, ANtiOnline put out an article the other day,

PIX has an issue with SMTP traffic, it will allow trafiic through and may allow for compromise on mis-configured or older SMTP setups. There is no workaround nor any fix, Cisco is suggesting using another way of securing your smtp server.

Sorry for what seems like a bit of a dig, it's not meant as such,
I agree with the previous poster, if it ain't broke, don;t fix it, but if you really want to change, keep in mind:
Linux ( as of ipchains, not sure with iptables) is a fast firewall, it reads from teh bottom up on the rules file and the first match counts. This makes for fast processing.

BSD, uses berkeley packet filter and reads from the top down with a last match counts ideal. this is slower, but it is much more thorough. that packet will pass through every rule applicable to itself and see what matches and what doesn't. the read is also from the top down, this is a much more understandable format to write rules in (for most, anyway).
It somes to what you want to be saddled with, and which one can you config better/recover faster? Assuming this is your firewall, I am also assuming that you'll want to run SNort or something equally useful inside. A firewall is only a barrier, an IDS is a tool.

Now, if I could go religious on you for a minute...

I've heard from many of the Linux advocates that I work with that "standardizing on one operating system is EXACTLY what is wrong with the Windows approach, that is why they champion Open Source and Linux. Why then, does EVERY ONE of them want EVERYONE to run EVERYTHING on Linux?!?! Isn't that really the same crap in a different pile? I'm not down on Linux, and I don't hate Microsoft, they have done some things I think are fine, but I really think that some of the zealots I work with (I'm not inclusive, I'm only ranting about the ones I know) ought ot take a look at what they are saying and compare it to the Microsoft literature. They might be surprised at how alike they sound in some respects.

I'll get down now,

loadc

loadc

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LEARN ABOUT DEBIAN

shaperd

shaperd(8)						      System Manager's Manual							shaperd(8)

NAME

       shaperd - traffic shaper for tcp-ip networks

SYNOPSIS

       shaperd [-h] [-v] [-c file ]

DESCRIPTION

       shaperd is a user-mode program that can shape traffic passing through a linux box. As it runs as a normal daemon process, packet forwarding
       to/from the kernel can be done by the BSD divert sockets layer (available as a patch for the linux kernel) or by the ipq packet	forwarding
       library that comes with kernel 2.4.

       The  configuration  is  made  via  a  single text file, you can force a reload by sending a SIGHUP. Logs are routed via syslog, with prior-
       ity=info, facility=daemon.

       Please note that, for the moment, you must instruct the kernel which packets to forward to shaperd.  This can be done,  for  example,  with
       the  ipchains(8)  utility under Linux 2.2, or with iptables(8) under Linux 2.4. Also, note that if a packet does not match any of the rules
       in the configuration file, it will be ignored by shaperd (but it will be logged if the log level is high enough).

OPTIONS

       -c config-file
	      Tells the daemon to get its configuration from this config-file

       -h     Summarizes command line options

       -v     Prints version information

SEE ALSO

       ipchains(8);  iptables(8);  libipq(3);  Linux's	divert	sockets  site,	http://www.anr.mcnc.org/~divert/index.shtml  ;	Netfilter's  site,
       http://netfilter.samba.org. Linux Advanced Routing & Traffic Control, http://ds9a.nl/lartc.

BUGS

       do i kill them? become their friend?
       do i eat them? raw or well done
       do i trick them? i ... i don't think they're that dumb
       do i join them? looks like that's the one
       i got bugs on my skin tickle my nausea
       i let it happen again they're always taking over
       i see they surround me i see ... see them deciding my fate
       oh that which was once was once up to me ... now it's too late
       i got bugs in my room one on one
       that's when i had a chance
       i'll just stop now i'll become naked, and with them i'll become one

AUTHOR

       Leandro Santi <lsanti@fi.uba.ar>

																	shaperd(8)