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I have installed OMSA on a server and the dsm_om_connsv service is running. I have found, in the past, this always binds to an IPv6 socket only;

# netstat -lnp
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 0.0.0.0:389             0.0.0.0:*               LISTEN      4988/slapd      
tcp        0      0 0.0.0.0:3306            0.0.0.0:*               LISTEN      4901/mysqld     
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      4556/sshd       
tcp6       0      0 :::389                  :::*                    LISTEN      4988/slapd      
tcp6       0      0 :::22                   :::*                    LISTEN      4556/sshd       
tcp6       0      0 :::1311                 :::*                    LISTEN      18536/dsm_om_connsv

Unfortunately I don't have end to end IPv6 connectivity to this particular server, so does anyone know how I can make it bind to an IPv4 socket instead? Also, why does this happen. Has Dell made OMSA favour IPv6 or has this server chosen IPv6 over IPv4 (default kernel choice perhaps)?

Many thanks for your time and help.

# uname -a
Linux boxy 2.6.24-30-server #1 SMP Tue Nov 8 13:44:13 UTC 2011 i686 GNU/Linux
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2 Answers 2

up vote 2 down vote accepted

Turns out that sockets listening as TCP6 accept IPv4 and IPv6 connections so this works over IPv4 :)

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Under Linux an application can choose if an IPv6 socket works for both IPv6 and IPv4 (which are then represented as IPv4-mapped IPv6 addresses) or only for IPv6. This is controlled through setsockopt with the IPV6_V6ONLY flag. The default value for this flag is exposed through /proc/sys/net/ipv6/bindv6only, which is 0 (off: use both IPv6 and IPv4 on IPv6 sockets) by default.

This is documented in http://www.kernel.org/doc/man-pages/online/pages/man7/ipv6.7.html

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