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Full Discussion: Packet going out of wrong interface due to OS automatically added cache route with lower metric
Special Forums IP Networking Packet going out of wrong interface due to OS automatically added cache route with lower metric Post 303004795 by msr1981 on Monday 9th of October 2017 07:34:34 AM
Old 10-09-2017
Packet going out of wrong interface due to OS automatically added cache route with lower metric
RHEL 7.0, IPV6

Scenario:
I have routed specific network using network scripts.
1. "ip -6 route show" shows that route has been added. ( with metric 1024)
2. Ping of the specific IP through that route is successful.
3. Now after few days, for some reason, we see that cache route appears for that given destination IP with lower metric ( which is actually trying to take it through interface/bond of the default route.)Ping to that destination IP fails then because packet is going out of wrong interface.
4. If I delete that cache route, again the packet starts going out of the correct interface ( which is not interface of the default route) and ping is successful.

Has anyone faced similar issue with REHL. I am using RHEL 7
Questions:
Q1. In what situation OS will try to route through default, even if static route for specific IP/network exists.
Q2. How to configure the route so that OS does not fall back on default route if specific interface is assigned for a specific ip/network by static configuration. Please note, we can not delete the default route.
Q3. Even if OS is creating cache route for some temporary situation, why is it not detecting that situation has normalized and why it is not deleting the automatically created cache route then. ( assuming that some temporary network side failure caused this issue )

Please note, we are not facing this issue for IPV4. We are facing this with IPV6
Can anyone suggest on how to permanently resolve this situation ?
 

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LEARN ABOUT OPENSOLARIS

make_sockdfr

MAKE_SOCKDFR(8) 					      System Manager's Manual						   MAKE_SOCKDFR(8)

NAME

       make_sockdfr -  Generates frozen route file for SOCKS server

SYNOPSIS

       make_sockdfr [infile [outfile] ]

DESCRIPTION

       make_sockdfr reads in a plain-text route file for the SOCKS server and produces a frozen route file as the output.

       Both  arguments	are optional. The default for infile is /etc/sockd.route; the default for outfile is /etc/sockd.fr. You may specify infile
       while omitting outfile, but you cannot specify outfile without also speficying infile.

       The contents of the frozen route file is essentially the memory image of the parsed input file. Using the frozen route file can reduce  the
       start-up delay of the SOCKS server program since it no longer has to parse the file contents.

       When  the  SOCKS  server starts, it always looks for the frozen route file /etc/sockd.fr first. If that file is not found, it then tries to
       use the plain-text route file /etc/sockd.route. If you use frozen route file, you must remember to run make_sockdfr every  time	after  you
       modify the plain-text file or the SOCKS server will continue to use the frozen version of a previous route file.

       To find out the contents of a frozen route file, use dump_sockdfr.

FILES

       /etc/sockd.fr, /etc/sockd.route

SEE ALSO

       dump_sockdfr(8), sockd.fr(5), sockd.route(5)

AUTHOR

       Ying-Da Lee, yingda@esd.sgi.com or yingda@best.com

								    May 6, 1996 						   MAKE_SOCKDFR(8)
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