[plug] no route to host(s), but can ping?

[Daniel Pittman]

Lucas van Staden <lvs at dedmeet.com> writes:

> Just can't figure this out, and I am sure I am missing something
> obvious here.

You missed a firewall, or a lack of IPv6, somewhere in there. :)

> Box is debian hardy 8.04
> Can for example ping www.google.com:
>
> PING www.l.google.com (66.249.89.104) 56(84) bytes of data.
> 64 bytes from jp-in-f104.google.com (66.249.89.104): icmp_seq=1 ttl=244
> time=276 ms

So, ICMP echo messages get through, but...

> but cannot traceroute: (unknown host?)
>
> --- www.l.google.com ping statistics ---
> 2 packets transmitted, 1 received, 50% packet loss, time 1004ms
> rtt min/avg/max/mdev = 276.041/276.041/276.041/0.000 ms
> web at webserver ~ $ sudo traceroute6 www.google.com
> traceroute: unknown host www.google.com

...and you sure you meant to use IPv6 rather than IPv4 in the trackroute?

> Found that my smtp server stopped sending mail, with error 'no route to host'
>
> 2008-11-28 11:21:51 1L5szN-0003qk-OM aspmx.l.google.com [209.85.163.27] No
> route to host

[...]

> Same issue, I can ping those, but I cannot traceroute.
> I can access internet, downloads etc fine from the box.
>
> Any Ideas what I am missing here? Or what to look at?

Well, my first check would be if IPv4 traceroute worked, but it might
not.  You might also check if 'tcptraceroute' can connect, or where it
tells you that the connection is blocked.

However, my guess would be that a firewall on your system, or at your
ISP, is preventing the communication.

Regards,
        Daniel