I have two SRX240's clustered together. The clustering is configured with 2 redundancy groups and then 3 RETH's.

reth1 is connected to our internet connection via ge-0/0/5 and ge-5/0/5. Our internet connection is a 100mbps each way leased line. We have to make sure they we specify disable the auto negotiate settings and manually set the speed and full duplex mode.

Here is the config showing those interfaces

cluster {
    reth-count 3;
    redundancy-group 0 {
        node 0 priority 100;
        node 1 priority 99;
    redundancy-group 1 {
        node 0 priority 100;
        node 1 priority 99;
        interface-monitor {
            ge-0/0/5 weight 255;
            ge-5/0/5 weight 255;

interfaces {
    ge-0/0/5 {
        speed 100m;
        link-mode full-duplex;
        gigether-options {
            redundant-parent reth1;
    ge-5/0/5 {
        speed 100m;
        gigether-options {
            redundant-parent reth1;
    reth1 {
        redundant-ether-options {
            redundancy-group 1;
        unit 0 {
            family inet {

The upstream NTE sits on IP address (IP's changed).

My connection works fine, I get close to maximum download speeds for the line speed. I have low latency and everything else that you would expect. However every now and then I suddenly can't ping the upstream NTE. The connectivity just stops.

If I check the interface status it shows as being up.

gareth@FW01> show interfaces ge-0/0/5
Physical interface: ge-0/0/5, Enabled, Physical link is Up
  Interface index: 139, SNMP ifIndex: 527
  Link-level type: Ethernet, MTU: 1514, Link-mode: Full-duplex, Speed: 100mbps,
  BPDU Error: None, MAC-REWRITE Error: None, Loopback: Disabled,
  Source filtering: Disabled, Flow control: Enabled, Auto-negotiation: Enabled,
  Remote fault: Online
  Device flags   : Present Running
  Interface flags: SNMP-Traps Internal: 0x0
  Link flags     : None
  CoS queues     : 8 supported, 8 maximum usable queues
  Current address: 00:10:de:ff:20:01, Hardware address: 08:81:f4:cd:a1:05
  Last flapped   : 2013-05-16 01:35:08 UTC (03:39:01 ago)
  Input rate     : 7144 bps (10 pps)
  Output rate    : 34488 bps (58 pps)
  Active alarms  : None
  Active defects : None
  Interface transmit statistics: Disabled

  Logical interface ge-0/0/5.0 (Index 74) (SNMP ifIndex 528)
    Flags: SNMP-Traps 0x0 Encapsulation: ENET2
    Input packets : 20966964
    Output packets: 13453431
    Security: Zone: Null
    Protocol aenet, AE bundle: reth1.0   Link Index: 0

gareth@FW01> show interfaces reth1.0
  Logical interface reth1.0 (Index 68) (SNMP ifIndex 578)
    Flags: SNMP-Traps 0x0 Encapsulation: ENET2
    Statistics        Packets        pps         Bytes          bps
        Input :      20967161         12   19068965037         9320
        Output:      13454302         44    3387733487        29088
    Security: Zone: untrust-internet
    Allowed host-inbound traffic : ping
    Protocol inet, MTU: 1500
      Flags: Sendbcast-pkt-to-re
      Addresses, Flags: Is-Preferred Is-Primary
        Destination:, Local:,

The reason for the last flap was because I changed the network cable to rule that out. Unplugging the cable and connecting a new one causes the connection to come back. I am a little reluctant to trust it at the moment.

Does anyone have any other things I can look at if it happens again?

I did find the following post http://kb.juniper.net/InfoCenter/index?page=content&id=KB16672 which says it should work on supported versions.

The releases, specifically for High End SRX devices, are 11.2R1, 11.1R1, 10.3R3, 10.4R2, 10.2R4 or later. For Branch SRX devices, this is supported only from Junos 11.1R4, 11.2R2, and 11.4R1 onwards.

I am running version 11.2R4.3

  • Can you clarify the NTU you're plugging into, do you have two ports on it, or one port and a switch in between?
    – LapTop006
    May 18, 2013 at 11:08
  • It's a World Wide Packets Lightening Edge 45. It has a 4 port switch built into it. May 20, 2013 at 6:19

1 Answer 1


Here's some version info that should help. I think that the other thing that immediately strikes me is autonegotiation being disabled, which shouldn't be necessary. Is this something that your provider is asking for, or based on learned behaviors? I recommend reading what's out there, since autonegotiation has been recommended for over 10 years. Anything you're connecting to should work fine with it as well (the last time I had issues was on a 3500XL - we're talking ooooold). Check out:


First off, Junos 11.4R7.5 is the supported release recommended for SRX240, as of 8 April 2013, per JTAC (since you mentioned versions).

http://kb.juniper.net/InfoCenter/index?page=content&id=KB21476 (need login)

Also, JTAC recommends EEOL releases on SRX or J Series for IPsec features (may or may not apply, but FYI). (For me, the only releases available for SRX240H on juniper.net are 10.4, 11.4, and 12.1 - that may help set your expectations on what to run.)

http://www.juniper.net/alerts/viewalert.jsp?txtAlertNumber=PSN-2013-01-822&actionBtn=Search (need login)

You are also running a version that was released before the malformed TCP vulnerability came out. I shudder to think that a live exploit exists, but you definitely need to be on versions that were published around January or February 2013, or later. The versions you need for 11.2 are 11.2R5.5 or 11.2R7.5 (or higher)


I mentioned versions because the SRX is a 'rapidly evolving' platform as well, and anecdotal evidence and hearsay suggests that you'll want to upgrade more frequently.

  • As for the auto-neg we have been told by our provider (Virgin - Big Red) to manually assign the speeds. An email from early 2011 said Hi Gareth, Our network team have advised to try the below:- Hard code the WAN interface to the speed that they have ordered 10, 100. or 1000 and duplex set to full. then have the LAN interface set to auto auto. May 16, 2013 at 11:54
  • Steps I will take will be 1. Update the firmware and then 2. I'll check with our provider and see if we are still required to use hard coded speeds/duplex settings. Thanks for you comment, hopefully after tonight I won't see anymore issues! May 16, 2013 at 11:55
  • 1
    I think monitoring your ethernet links for errors is important as well. (might as well post extensive versions here). If hard-set speed/duplex was an issue, that would be the place to look. Running something like smokeping from internal IPs out (e.g. to your router, your near-side of the /30, provider-side of the /30 and someplace on the Internet), as well as from some place on the Internet to each of the points of connectivity could visualize connectivity issues. May 16, 2013 at 12:02
  • Just to provide an update to this, I was advised to still hard code the speed and duplex settings :( and I also updated to the latest Junos release. So far I've not run into my original issue. Thanks for you help May 22, 2013 at 17:36

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