el-musico

Q: Strange network hang

I have experienced a kind of a strange network hang situation.

 

I have a Mac Mini with OS X 10.10.5. Everything worked fine for years since this morning. Suddenly I could not open an http connection to a specific device (Synology NAS) using Safari (http://a.b.c.d:5000). I could not open the connection using Safari and Firefox. Even wget http://a.b.c.d is handing. Finder with smb://a.b.c.d was also handing. At the same time it was possible to open connections from my Mac Mini to other devices and the internet. I could ping the NAS from my Mac Mini. It is also possible to open the DSM interface on http://a.b.c.d:5000/ and  smb://a.b.c.d from a linux system which is in the same network. After disabling all network interfaces and rebooting the Mac Mini it works if I just enable the WLAN only. If I enable the cable connection the connection to the Sinology NAS hangs again. I have cleared the ARP and DNS cache, but it is still the same. Any help is appreciated.

Posted on Aug 8, 2016 9:02 AM

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Q: Strange network hang

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  • by rccharles,

    rccharles rccharles Aug 8, 2016 12:05 PM in response to el-musico
    Level 6 (8,464 points)
    Classic Mac OS
    Aug 8, 2016 12:05 PM in response to el-musico

    http://a.b.c.d:5000

     

    I this a numeric address?

    like 192.168.n.n

    or 10.n.n.n

     

    These are local addresses and are not routeable in the internet.  They repeat for every computer on the internet. It's ok to post.

     

    Could some other device have the same ip address?

     

    R

  • by Eric Root,

    Eric Root Eric Root Aug 9, 2016 10:17 AM in response to el-musico
    Level 9 (69,891 points)
    iTunes
    Aug 9, 2016 10:17 AM in response to el-musico

    Have you tried shutting down the external drive, unplugging it, and then restarting it?

  • by el-musico,

    el-musico el-musico Aug 9, 2016 10:26 AM in response to el-musico
    Level 1 (5 points)
    Mac OS X
    Aug 9, 2016 10:26 AM in response to el-musico

    Thanks for answering. I have fixed the problem. I was a problem of the network setup. I had to exchange my DSL router because of a hardware problem. I'm using the the router  also as DHCP server. I have used the same network address and DHCP range, but  all devices got new IP addresses. In addition in the previous setup I have enabled jumbo frames for my NAS devices. The mismatch between the device configuration of the switch and the NAS devices has caused. After syncing the configuration of the switch and the NAS devices everything worked fine. Sometime symptoms indicate the complete wrong direction. Thanks again!