RE: [Declude.JunkMail] NOW OT: ICMP

2004-07-09 Thread Russ Uhte \(Lists\)
At 04:44 PM 7/9/2004, Andy Schmidt wrote: >> one case that comes to mind is PMTU. I've seen first hand instances where a corporation blocked all ICMP traffic, and then some of my users couldn't access that companies website. For whatever reason, the remote web server had a smaller than normal MTU

RE: [Declude.JunkMail] NOW OT: ICMP

2004-07-09 Thread Andy Schmidt
>> one case that comes to mind is PMTU. I've seen first hand instances where a corporation blocked all ICMP traffic, and then some of my users couldn't access that companies website. For whatever reason, the remote web server had a smaller than normal MTU size << Yes - ICMP should be blocked

Re: [Declude.JunkMail] NOW OT: ICMP

2004-07-09 Thread Russ Uhte \(Lists\)
At 03:45 PM 7/9/2004, Doug Anderson wrote: Actually Russ, ICMP still works. Can you ping 127.0.0.1, the local loop back? Can you ping other items on your local network? It comes down intranet vs internet separated by a firewall. Many corporations kill ICMP externally, but it works fine internally a

Re: [Declude.JunkMail] NOW OT: ICMP

2004-07-09 Thread Doug Anderson
er go through a security audit like we do, you'll understand. - Original Message - From: "Russ Uhte (Lists)" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Friday, July 09, 2004 3:16 PM Subject: Re: [Declude.JunkMail] NOW OT: ICMP > At 03:03 PM 7/9/2004, Dan

RE: [Declude.JunkMail] NOW OT: ICMP

2004-07-09 Thread Dan Horne
Ah, but ICMP does still work on your machine. You can still ping internally. It's just that those machines outside your firewall can't REACH your machine with ICMP. There is nothing in the RFC that even implies that I must allow all ICMP packets to reach my network. Even if you're using a softw

Re: [Declude.JunkMail] NOW OT: ICMP

2004-07-09 Thread Russ Uhte \(Lists\)
At 03:03 PM 7/9/2004, Dan Horne wrote: "if you block ICMP, you break IP. That's the bottom line, and nobody can argue that." Sorry, but I can and will argue with that. ICMP relies on IP, not the other way around. IP works with or without ICMP. RFC792, which defines ICMP, states "The purpose of