[Gllug] pinging through NAT very slow

[John Winters]

Martin A. Brooks wrote:
> I have a machine quite newly installed running a simple NAT. Generally, 
> it works fine except for it's incredibly slow and gives some packet loss.
> 
> 
> 
> 
> martin at martin-laptop:~$ ping www.google.com
> PING www.l.google.com (216.239.59.104) 56(84) bytes of data.
> 64 bytes from 216.239.59.104: icmp_seq=1 ttl=245 time=20.7 ms
> 64 bytes from 216.239.59.104: icmp_seq=2 ttl=245 time=17.4 ms
> 64 bytes from 216.239.59.104: icmp_seq=3 ttl=245 time=19.3 ms
> 64 bytes from 216.239.59.104: icmp_seq=5 ttl=245 time=19.7 ms
> 64 bytes from 216.239.59.104: icmp_seq=6 ttl=245 time=77.9 ms
> 64 bytes from 216.239.59.104: icmp_seq=7 ttl=245 time=33.3 ms
> 
> --- www.l.google.com ping statistics ---
> 7 packets transmitted, 6 received, 14% packet loss, time 26265ms
> 
> 
> Whereas from the server:
> 
> off0crm01:~# ping www.google.com
> PING www.l.google.com (66.102.9.99) 56(84) bytes of data.
> 64 bytes from 66.102.9.99: icmp_seq=1 ttl=246 time=20.4 ms
> 64 bytes from 66.102.9.99: icmp_seq=2 ttl=246 time=17.1 ms
> 64 bytes from 66.102.9.99: icmp_seq=3 ttl=246 time=23.1 ms
> 64 bytes from 66.102.9.99: icmp_seq=4 ttl=246 time=22.7 ms
> 64 bytes from 66.102.9.99: icmp_seq=5 ttl=246 time=40.3 ms
> 64 bytes from 66.102.9.99: icmp_seq=6 ttl=246 time=27.9 ms
> 
> --- www.l.google.com ping statistics ---
> 6 packets transmitted, 6 received, 0% packet loss, time 5006ms
> rtt min/avg/max/mdev = 17.145/25.294/40.349/7.473 ms

The actual response times there seem just the same and yet the total
time is much more (and your one lost packet could be accounted for by
when exactly you hit Ctrl-C.  This suggests that ping is taking a long
time *between* packets, rather than waiting a long time for each
response.  It could easily be a DNS issue.  Test that with:

ping -n www.google.com

HTH
John
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