Take the 2-minute tour ×
Server Fault is a question and answer site for professional system and network administrators. It's 100% free, no registration required.

Suppose having an routing table in which the default-route is missing can a router work without a default-route or the table is incomplete?

and having these two entries is also legit or there is an overlap problem for the network addresses?

Type        Network            Next Hop
s           130.192.16.0/22    130.192.11.254
s           130.192.16.8/28    130.192.11.254
share|improve this question
    
Did you mean /29 in the second line? –  mulaz Feb 4 '13 at 17:11
    
No it's 28 and I'm asking because if it's YES on my both questions then there the second address is not an valid network address. –  Lucian Enache Feb 4 '13 at 17:12
1  
130.192.16.8/28 it's not a valid route. 130.192.16.8/29 or 130.192.16.0/28 are. - pastebin.com/UKDr37fd –  mulaz Feb 4 '13 at 17:14
    
Thanks You've answered my problem –  Lucian Enache Feb 4 '13 at 17:19
add comment

1 Answer 1

up vote 3 down vote accepted

For the first question, the answer is 'yes'. The router will work, but only the networks in the routing table will be accessible. For everything else, you'll get a "destination host unreachable".

For the second, if you have two (or more) overlaping networks, the longest-prefix-match will be used. So, if you want to access 130.192.16.9, the second route will be used (doesn't matter in your case, since both use the same gateway), because the the match is longer (more bits match the network ID/mask).

If you have:

10.0.0.0/8 via gw1
10.0.0.0/16 via gw2
10.0.0.0/24 via gw3
10.0.0.0/30 via gw4

and want to ping 10.0.0.1, the packet will go via gw4, since it matches more bits with the network id/mask then other routes.

Edit:

130.192.16.8/28

is not a valid route (if you use /28, 130.192.16.0 is a network ID). However 130.192.16.8/29 is a valid route.

share|improve this answer
    
thanks, still is it possible for the second address to get an error because that is not an valid network address ? –  Lucian Enache Feb 4 '13 at 17:09
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.