nanog mailing list archives

Re: Traffic to our customer's address(126.0.0.0/8) seems blocked by packet filter


From: Joe Abley <jabley () isc org>
Date: Wed, 3 Aug 2005 16:22:04 -0400



On 3 Aug 2005, at 16:15, Roy Badami wrote:


    Marlon> just remember that not all networks use '126.255.255.255'
    Marlon> as a broadcast address. there are non-broadcast networks
    Marlon> where that address is a 'host' one.

Surely the only networks on which this can be a host are:

       one using a /7 or shorter netmask
       a /31 (as per RFC3021)

[root@felix]# ifconfig lo0 inet 126.255.255.255 netmask 255.255.255.255 alias
[root@felix]# ping 126.255.255.255
PING 126.255.255.255 (126.255.255.255): 56 data bytes
64 bytes from 126.255.255.255: icmp_seq=0 ttl=64 time=0.088 ms
64 bytes from 126.255.255.255: icmp_seq=1 ttl=64 time=0.062 ms
^C
--- 126.255.255.255 ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max/stddev = 0.062/0.075/0.088/0.013 ms
[root@felix]#

Inserting the host route for 126.255.255.255/32 into an adjacent IGP is similarly straightforward.


Joe


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