My machine doesnt respond to any SYN or ICMP packets!

My machine doesnt respond to any SYN or ICMP packets!

Post by Henrik Storn » Mon, 05 Oct 1998 04:00:00

>Hi there. Here is a stumper. My Linux box (kernel 2.0.35) recieves its IP via
>DHCP. From that machine I can telnet, ping, ftp or whatever else flawlessly.
>However if a machine not on my Ethernet Segment tries to connect (or even
>ping) me nothing happens.

Check that your routing tables are setup correctly, i.e. you should have
a route to the local net through eth0, and a default route (if you have
internet access) through your gateway on the local network).

Henrik Storner  |  "testing? What's that? If it compiles, it is good,
                |   if it boots up it is perfect."
                |                                    Linus Torvalds


1. SYN flooding -- how can I respond?


hi Paul

this is not necessarily the answer to your question.

I asked myself the same question today, since i'm trying to
set up a working firewall myself. i use ipfwadm to log all
syn pakets coming to my fw machine for later study.

just out of curiosity i got myself a syn flooder (synk4) and
tested it against my test setup. the logfile got full of junk,
yes, but it doesn't help much i guess: the synk4 can generate
random source ips and send it with the paket, so you're not able to
trace it back.

hmm. i'd like to know where you got that log message. i configured
my kernel with CONFIG_SYN_COOKIES=y, but it doesn't log anything
as far as i can make out.

well, guess it didn't answer all your questions, but atleast
i added my .02


- --

- ->
- -> PGP Key fingerprint = F9 49 DC 2E A2 FC 5A 4C  91 70 8E AC 07 A7 27 98
- -> finger me for public key

Version: 2.6.3i
Charset: noconv
Comment: Processed by Mailcrypt 3.4, an Emacs/PGP interface


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