On 01/09/2013 17:04, Grant wrote: >>>>>> My laptop can't ping my remote system but it can ping others >>>>>> (google.com, yahoo.com, etc). I've tried disabling my firewall on >>>>>> both ends with '/etc/init.d/shorewall stop && shorewall clear'. Could >>>>>> my AT&T business ADSL connection on the remote system be blocking >>>>>> inbound pings? >>>>>> >>>>> Possible, have you tried pinging your remote system from a different >>>>> location? You may try http://www.downforeveryoneorjustme.com/ >>>> >>>> Sorry, wrong link: http://ping.eu/ping/ >>> >>> I get 100% packet loss when pinging from there. >> >> try an icmp traceroute, if you are lucky you'll get a result that tells >> you on which hop the pings cease to work: >> >> traceroute -I >> >> but do read the man page (traceroute is like ps in that there are many >> versions around and options don't always match up with what folk say on >> mailing lists) > > I did 'traceroute -w 30 -I ip-address' several times and the last IP > displayed is always the same. I looked it up and it's an AT&T IP > supposedly located about 1500 miles from my machine which is also on > an AT&T connection. Does this tell me anything?
Yes, it tells you that all hops up to that point at least respond to the kinds of icmp packets traceroute uses. The first hop that fails to answer isn't answering. You are looking for possible reasons why icmp might not be working out properly - that router is your first suspect. Admittedly, it might be blocking traceroute pings and still allow the responses you seek, but you have to start somewhere :-) The problem you are trying to track down is notoriously tricky to nail down exactly as too many ISPs out there obsessively block useful icmp traffic. They believe it's security. I believe it's security theatre and makes fault finding on a live network infernally difficult. Mick is on the right track - deal with each issue one by one till you hit paydirt. -- Alan McKinnon [email protected]
