[TriLUG] some TCP utilities ignore kernel routing table?

[Brian Henning]

Reporting as ordered, Sir!

The "from" host in this argument is universally 192.168.1.32, with the 
previously listed routing table.

1) Yes.  Lots of services run on 125; I'd know very quickly if I 
couldn't reach it.

2)
# ping 192.168.10.4
PING 192.168.10.4 (192.168.10.4) 56(84) bytes of data.
64 bytes from 192.168.10.4: icmp_seq=1 ttl=254 time=1.27 ms
64 bytes from 192.168.10.4: icmp_seq=2 ttl=254 time=1.23 ms

--- 192.168.10.4 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1001ms
rtt min/avg/max/mdev = 1.234/1.253/1.272/0.019 ms

3)
# traceroute -n 192.168.10.4
traceroute to 192.168.10.4 (192.168.10.4), 30 hops max, 40 byte packets
  1  192.168.1.125  0.237 ms  0.148 ms  0.133 ms
  2  192.168.1.125  0.132 ms !C  0.135 ms !C *

...dunno what !C means...manpage...  two possible meanings: "access to 
the host is prohibited" or "precedence cutoff in effect."

Gah.  Wish I'd taken that networking class.

Now what?
~Brian



Tanner Lovelace wrote:
> On 1/10/06, Brian Henning <brian at strutmasters.com> wrote:
> 
>>Hi Folks,
>>   Just wondering if someone could shed some light on why it seems that
>>some tcp utilities seem to ignore the kernel routing table.  For
>>example:  (Sorry about the wrapping..)
>>
>>% /sbin/route -n
>>Kernel IP routing table
>>Destination     Gateway         Genmask         Flags Metric Ref    Use
>>Iface
>>192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 eth0
>>192.168.10.0    192.168.1.125   255.255.255.0   UG    0      0        0 eth0
>>0.0.0.0         192.168.1.1     0.0.0.0         UG    0      0        0 eth0
>>
>>% telnet 192.168.10.4
>>Trying 192.168.10.4...
>>telnet: Unable to connect to remote host: No route to host
>>
>>Um.  Yes there is a route to the host.  Right there in the kernel
>>routing table.  It says to go by way of .1.125.
>>
>>What gives?  I think this also affects the cups printing manager as it
>>does nothing but report no printer at the specified address/port.
> 
> 
> 1. Have you actually verified that you can reach .1.125?
> 2. Try a traceroute to 192.168.10.4.
> 3. Try a ping to 192.168.10.4.
> 
> Report back.
> 
> Cheers,
> Tanner
> --
> Tanner Lovelace
> clubjuggler at gmail dot com
> http://wtl.wayfarer.org/
> (fieldless) In fess two roundels in pale, a billet fesswise and an
> increscent, all sable.

-- 
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Brian A. Henning
strutmasters.com
336.597.2397x238
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