nanog mailing list archives
RE: Common operational misconceptions
From: George Bonser <gbonser () seven com>
Date: Fri, 17 Feb 2012 05:42:36 +0000
-----Original Message----- From: Owen DeLong Sent: Thursday, February 16, 2012 8:48 PM To: Masataka Ohta Cc: nanog () nanog org Subject: Re: Common operational misconceptions On Feb 16, 2012, at 5:11 PM, Masataka Ohta wrote:Andreas Echavez wrote:*Why disabling ICMP doesn't increase security and only hurts theweb**(path MTU discovery, diagnostics)That PMTUD works is a misconception.It actually works where people have not made active efforts to break it.
Modern (RFC 4821) PMTUD that is used by default by Solaris and Microsoft does not require ICMP and works well. For Linux you have to enable it: /proc/sys/net/ipv4/tcp_mtu_probing = 1 or 2 (I believe the default is still 0 which means it relies on ICMP for PMTUD by default and you must turn on RFC 4821 PMTUD). If you're relying on ICMP for PMTUD, still, then yeah, you probably run into problems from time to time but fewer stacks use that method of PMTUD these days.
Current thread:
- Re: Common operational misconceptions, (continued)
- Re: Common operational misconceptions Masataka Ohta (Feb 16)
- Re: Common operational misconceptions Josh Hoppes (Feb 16)
- Re: Common operational misconceptions Masataka Ohta (Feb 16)
- Re: Common operational misconceptions Valdis . Kletnieks (Feb 16)
- Re: Common operational misconceptions Masataka Ohta (Feb 16)
- Re: Common operational misconceptions Valdis . Kletnieks (Feb 16)
- Re: Common operational misconceptions Masataka Ohta (Feb 16)
- Re: Common operational misconceptions Owen DeLong (Feb 16)
- Re: Common operational misconceptions Masataka Ohta (Feb 16)
- Re: Common operational misconceptions Masataka Ohta (Feb 16)
- Re: Common operational misconceptions Owen DeLong (Feb 16)
- RE: Common operational misconceptions George Bonser (Feb 16)
- Re: Common operational misconceptions Masataka Ohta (Feb 16)
- RE: Common operational misconceptions George Bonser (Feb 17)
- Re: Common operational misconceptions Masataka Ohta (Feb 19)
- Re: Common operational misconceptions Valdis . Kletnieks (Feb 20)
- RE: Common operational misconceptions George Bonser (Feb 20)
- Re: Common operational misconceptions Masataka Ohta (Feb 20)
- RE: Common operational misconceptions George Bonser (Feb 20)
- Re: Common operational misconceptions Masataka Ohta (Feb 20)
- Re: Common operational misconceptions Steven Bellovin (Feb 20)
- Re: Common operational misconceptions Masataka Ohta (Feb 20)