Hi Adam, On Fri, 5 Nov 2010, Adam Hardy wrote:
> I have a problem with some software running on a windows machine on the > LAN where the company who wrote the sofware say that there must be > something wrong with my internet connection, but can't help any further. > > I'd like to know what tests I can run to verify that my config and my > firewall are OK, especially regarding PMTU. > > I tried running without my firewall but it makes no difference so maybe > it's something else out there with my ISP before it hits the public net. Simply running "without a firewall" is not enough to make it work. The firewall has to actively reverse NAT the ICMP Unreachable messages that it receives from the Internet for PMTU to work. > What can I do with ping? This ping command gives suspicious results: > > ping -s 1473 mktgw1.ibllc.com You didn't tell us the results. You also didn't tell us what the actual problem is with the software. I would forget about ping and run Wireshark or tcpdump on your firewall, capturing packets on both sides and comparing the differences. Look for a packet received on one side that's not forwarded correctly to the other, or look for the point where the conversation stops. I would also consider trying a different Internet connection, e.g. a 3G dongle or a friend's DSL router/connection. Cheers, Chris. -- Aptivate | http://www.aptivate.org | Phone: +44 1223 760887 The Humanitarian Centre, Fenner's, Gresham Road, Cambridge CB1 2ES Aptivate is a not-for-profit company registered in England and Wales with company number 04980791. _______________________________________________ smokeping-users mailing list [email protected] https://lists.oetiker.ch/cgi-bin/listinfo/smokeping-users
