Re: ping packet loss when size gt 1500
On Sat, 16 Oct 2010 20:11:46 +0100, Adam Hardy wrote:
> I thought I knew enough to keep my own home LAN going but I'm stuck on
> this one and I can't work out what to do next. In fact I thought
> everything was fine until I tried pinging with big packet sizes.
> ping -s 1472 www.bbc.co.uk
> ping -s 1472 18.104.22.168
> works fine, no packet loss ever.
> ping -s 1473 www.bbc.co.uk
> works fine too.
> ping -s 1473 22.214.171.124
> results in 100% packet loss.
It can be a black hole router.
Most firewalls block pings that send packets bigger than normal (32-64
bytes) to avoid "ping of death" and "blocking icmp fragment".
> I have a bizarre problem with the server at 126.96.36.199, which is an
> internet broker whose server keeps disconnecting when making data
> requests. Their support is blaming the problem on me.
I cannot load that site (188.8.131.52) on a web browser :-?
sm01@stt008:~$ host 184.108.40.206
220.127.116.11.in-addr.arpa domain name pointer mktgw1.ibllc.com.
And by its name, seems like a gateway.
> 18.104.22.168 is used by a huge number of clients and I apparently am
> the only one suffering.
> Could it be something on my LAN? Or could it be my ISP (British Telecom)
> whose DNS server will randomly go down for a while and then come back
> (not in sync with the appearance of this problem though) - I thought I'd
> state that to give an idea of the ISP's reliability.
> Or is this ping problem definitely something I can sort out and perhaps
> solve it?
You can try by reducing your MTU to 1400.