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    Synology Dynamic Link Aggregaton on ProCurve 2910

    November 18th, 2014

    The Synology NAS have three network cables connected to the switch.
    (post 1, 2 and 3).

    On the HP ProCureve Switch:
    trunk 1,2,3 trk2 lacp
    vlan 3 untag trk2

    show vlans
    show trunks

    Write memory

    iptables on linksys WRT54G – add FTP and RDP rule

    March 23rd, 2010

    How du you configure and allow FTPS and RPD from a specific public IP on a linksys wrt54g router with the dd-wrt firmware?

    iptables -t nat -I PREROUTING -s 85.x.x.2 -p tcp –dport 3389 -j DNAT –to
    iptables -I FORWARD -d -p tcp –dport 3389 -j ACCEPT
    iptables -t nat -I PREROUTING -s 85.x.x.2 -p tcp –dport 60000:61000 -j DNAT –to
    iptables -I FORWARD -d -p tcp –dport 60000:61000 -j ACCEPT
    iptables -t nat -I PREROUTING -s 85.x.x.2 -p tcp –dport 990 -j DNAT –to
    iptables -I FORWARD -d -p tcp –dport 990 -j ACCEPT

    Block outgoing emails except from the mail server

    December 8th, 2008

    By default all clients on the LAN can act as a mail server. Maybe you have a “real” mail server. Now a hacker steals one of your client pc’s and uses it to send out SPAM.

    How do you configure the firewall so only the “real” mail server can send out emails?

    You do it with an access-list on the inside interface. This way you can control the outgoing smtp traffic and only allow one LAN IP to send out emails.

    access-list acl_out permit tcp host any eq 25
    access-list acl_out deny tcp any any eq 25
    access-list acl_out permit ip any any
    access-list acl_out permit icmp any any
    access-group acl_out in interface inside

    Test network speed with iperf

    June 17th, 2008

    You can test your network speed with the program iperf. It runs under all most used operating systems. The windows binary file can be found here:

    The file iperf.exe is used as client AND server.
    The basic idea is that the client UPLOADES an amount of data to the server.
    The speed of the transfer is then calculated.

    For a deeper introduction watch this Flash guide.

    An example:
    Server: iperf.exe -s
    Client: iperf.exe -c <server-ip>
    (Speed is now uploaded to the server)

    Use: iperf.exe –help to see options


    Test up and then down:

    C:\>iperf.exe -c -r
    Server listening on TCP port 5001
    TCP window size: 8.00 KByte (default)
    Client connecting to, TCP port 5001
    TCP window size: 63.0 KByte (default)
    [1876] local port 3975 connected with port 5001
    [ ID] Interval       Transfer     Bandwidth
    [1876]  0.0-42.9 sec  1.13 MBytes   221 Kbits/sec
    [1944] local port 5001 connected with port 4442
    [ ID] Interval       Transfer     Bandwidth
    [1944]  0.0-10.0 sec  41.5 MBytes  34.9 Mbits/sec


    Show IP

    August 26th, 2007

    Show your IP and network information.

    echo ‘
    echo $ip;

    /etc/network/interfaces configuration example

    August 18th, 2007

    Example 1 – Static IP

    # This file describes the network interfaces available on your system
    # and how to activate them. For more information, see interfaces(5).

    # The loopback network interface
    auto lo
    iface lo inet loopback

    # The primary network interface
    auto eth0
    iface eth0 inet static

    Example 2 – DHCP
    auto eth0 iface eth0 inet dhcp

    Remember the DNS configuration in /etc/resolv.conf

    Change (spoof) the MAC
    ifconfig eth0 hw ether 01:23:45:67:89:AB

    ISP Name and SMTP Servers

    August 18th, 2007


    Open DNS








    Test network speed

    August 2nd, 2007

    Ever tested network speed by downloading a big file?

    It could be nice to have a fast FTP server containing files in many different sizes.
    On this FTP server ftptest1.tele.dk files from 0 b to 100 MB

    Exit mobile version