[c-nsp] Ping getting IPv6 address, though IPv6 is not enabled.

[Joseph Mays]

Got something going on on a router that seems strange. To me, anyway.

I have a router that does not have IPv6 enabled, nor is IPv6 being used in the network it’s on. “ipv6” does not even occur anywhere in the config.

On any addresses it looks up the IPv4 address fine, and can route to that address. But when I ping something like www.yahoo.com it grabs the IPv6 address and tries to ping that. And fails, of course. How do I get it to stop preferring IPv6 addresses?

core-gw1.noc#show ip route www.yahoo.com
Translating "www.yahoo.com"...domain server (216.24.27.4) [OK]

Routing entry for 98.139.128.0/17
  Known via "bgp 7333", distance 20, metric 126041
  Tag 174, type external
  Last update from 38.122.142.5 1w0d ago
  Routing Descriptor Blocks:
  * 38.122.142.5, from 38.122.142.5, 1w0d ago
      Route metric is 126041, traffic share count is 1
      AS Hops 3

core-gw1.noc#show run | include ping
core-gw1.noc#show run | include icmp
permit icmp any host 216.24.27.41
core-gw1.noc#ping www.yahoo.com
Translating "www.yahoo.com"...domain server (216.24.27.4) [OK]

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2001:4998:58:C02::A9, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)