sticky ip = static ip?

Discussion in 'Cisco' started by jrefactors, Apr 14, 2005.

  1. jrefactors

    jrefactors Guest

    I have heard static IP and dynamic IP. I just heard someone saying
    about sticky IP, and I have no idea what is that, and I couldn't find
    any useful information about sticky IP.

    I want to ask if sticky IP is the same as static IP, that means the IP
    address is not changed?

    please advise. thanks!!
    jrefactors, Apr 14, 2005
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  2. jrefactors

    Carl Guest

    Look up port-security, sticky IPs exist there

    Carl, Apr 14, 2005
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  3. Sticky IP is one that does not change EVERY time that a connection is
    made but is not guaranteed to be the same indefinitely. I had a sticky
    IP with Pipex and had the same IP address for about 18 months. It only
    changed when I moved (house not ISP) and now have a dynamic address.

    The address is most likely to change if you disconnect for quite a long
    time (vague but depends upon ISP, the size of their address pool, number
    of customers etc).
    Stephen Bedford, Apr 14, 2005
  4. A sticky IP is one that is assigned by the methods used to assign
    dynamic IP addresses. However, they assign you the same IP address
    every time.

    There isn't any important distinction between static and sticky.

    Often sticky addresses are assigned via PPPoE. The people who make a
    big fuss over sticky are really complaining about PPPoE, although
    there really isn't any good reason to complain about that either.
    Neil W Rickert, Apr 14, 2005
  5. jrefactors

    Carl Guest

    doh, I meant mac's you are on about IPs

    /gone to sit in the corner
    Carl, Apr 14, 2005
  6. jrefactors

    Tom Stiller Guest

    Well, there is. Static IP address persist over time. Stick IP address
    persist as ling as the ISP chooses to let them. My IP address will
    change if I switch my cable modem connection from my router to my
    primary machine, even though both pieces of hardware have the same MAC
    address. It may also change if my ISP modifies the signal distribution
    Unless you have need to contact your machine from outside your local
    network. Some of us travel and have need to contact the home base on

    One way to resolve the issue, if you have need to, is to sign up for one
    of the free domain name mapping services (e.g. and install a
    client that keeps your name to IP address association up to date.
    Tom Stiller, Apr 14, 2005

  7. There's one other important distinction if you are trying to run a
    server on a "sticky" IP, especially a mail server. The reverse
    lookup will probably indicate that the IP is dynamic, and so will
    be listed in a number of widely-used block lists. Not a problem if
    you route outbound email through your ISP, but a potential liability
    if you're trying to run a mail server on the cheap!
    David C. Stone, Apr 14, 2005
  8. I'd like a router that would send a message to a specified email address
    whenever its WAN IP changed.
    Neill Massello, Apr 14, 2005
  9. Quite right. The static IP persists over time, until your ISP
    changes it.

    Right, but not different from static IPs. The different Tom sees
    between static and sticky exists only in his imagination.

    But that's a dynamic IP. It is neither static nor sticky.
    There are quite a few users on SBC dsl service, who have the SBC
    static package (usually described as sticky IPs), who have correct
    reverse DNS identifying their hostnames in a way that does not
    suggest dynamic. Hmm, they even have whois records on ARIN for their
    block of sticky IPs. The whois record does indicate that these
    are part of a larger SBC block.
    Neil W Rickert, Apr 14, 2005
  10. Sticky IPs are a term coined by non-Ameritech regions of SBC for a block
    of static IPs routed through a single connecting PPPoE IP (Ameritech
    has always done static adsl IPs that way). For example the PPPoE
    connection is configured like dynamic, but based on the login, the same
    block of static IPs are routed from the internet to that PPPoE IP.

    Not sure how those people would refer to our sdsl connection at work where
    WAN IP and default gateway of modem/router is unrelated to our /29 public
    static IPs behind it. Our ISP may use that WAN IP as a gateway to our
    subnet, but that is as transparent as normal internet routing to reach our
    public static IPs.
    David Efflandt, Apr 14, 2005
  11. I use and have an ADSL router. The canonical name for my
    machine points to the new IP adress when the IP changes on my router (
    every time router is restarted). I am using dnsupdate on my Mac to do
    this: So, not a mail message but you can
    always access your machine which I assume is what you want.
    Stephen Bedford, Apr 14, 2005
  12. jrefactors

    Scooby Guest

    I view the main distinction to be WHERE the address is configured. As a
    static address, it would be configured on the workstation. As a sticky
    address, the client would use dhcp and the server would assign that same
    address everytime based on dhcp configuration. I have some microsoft RAS
    users that require a static ip for a particular application. Instead of
    having the user configure their RAS entry with the static address, I just
    configure the user to get the same address. I'm sure you could accomplish
    the same thing by mac address as well.

    Scooby, Apr 14, 2005
  13. jrefactors

    Toby Guest

    Sticky IP, is basically a database within a device that ensures returning
    traffic is routed back to the sending device when load-balancing is in use.


    If 3 firewalls are used and traffic load balanced between them
    It is important that connection based trafic such as TCP uses the same
    firewall in both directions for a particular connection for it to function
    To achieve this a sticky IP database is set up in the device's either side
    of the F/W's noting the source IP address of the packet along with the IP
    address of the Firewall it was recieved from.
    Return traffic where the destination IP address already exists in the
    database as a source address will be delivered to the relevent firewall and
    not in a load balance round robin fashion. IP destinations not in the
    database will just use the round robin method to load balance.

    This of course could be taken to higher layers than just layer 3 but would
    possibly defeat the object as we want as little CPU time wasted on the
    single device feeding the 3 firewalls, as it is the CPU usage on the
    firewall that made us want to load share in the first instance.

    for more details


    Toby, Apr 14, 2005
  14. jrefactors

    Toby Guest

    I have read here that most peoples interpretation of Sticky IP is a DHCP
    allocated address that does not change, i.e. end user devices will accept an
    IP address from the ISP but the ISP itself is using a static allocation, or
    a generally static connection that can change dynamically under certain

    I have not seen this in use at configuration level (on Cisco routers), Does
    it actually exist or is it just a conceptual name for this behaviour? (my
    previous post shown below does however use Sticky IP in configuration on a
    CSM module in a Cisco L3 switch)

    I personally can not see the advantage of a service provider reserving an IP
    address for a customer and then allocating it dynamically (apart from ease
    of set up for the customers equipment) as surely this defeats the purpose of
    DHCP in preserving IPv4 address space on the assumption that not all users
    will be logged on so the ISP needs a smaller pool of addresses than the size
    of it's consumer base.

    I am also dubious about the use of sticky where a customer has used DNS to
    locate their IP address that has been stickily applied as the administration
    involved every time it changed would be stupid. Why not just have a static

    My last point is based on something I had not actually thought of before
    this post. What impact is the use of always on Broadband having on the IPv4
    address space? Previously home users had dial up DHCP allocated and due to
    charging/time restraints were not on 24/7 so did not use an IP address when
    offline. Broadbasnd in it's basic sence is simular in that if a DSL modem is
    used the IP address is allocated when the PC is on only. But with many
    people using DSL/Routers that are never turned off then surely the IPv4
    address space is taking a battering, If everyone used a router then we may
    as well all have a static IP address.



    My previous comments regarding sticky IP
    Toby, Apr 14, 2005
  15. So do sticky IP addresses.
    It's the same for static addresses.
    Then your IP address is neither static nor sticky.

    Maybe the term "sticky address" has a different meaning in cable
    networks than in DSL networks. If not, then I wonder what it is that
    you are suggesting.
    Your sticky address will continue to be the same. There won't be any
    problem contacting it.
    You are describing dynamic addresses, not sticky addresses.
    Neil W Rickert, Apr 14, 2005
  16. In practice, for the DSL world, it is usually IP addresses assigned
    during PPPoE negotiation, where the assigned IP does not change.
    That's only one of the purposes of DHCP.

    A computer needs to know its IP address, gateway router address, DNS
    server address, and perhaps other information. If you configure the
    IP address directly in customer equipment, then you have to also
    configure the other information. An ISP has more flexibility if that
    information can be assigned dynamically. It allows network
    reconfiguration without having to require customers to change their
    For what is usually called sticky IP, at least in the DSL world, you
    will always get the same IP. Therefore there are no serious problems
    in setting up DNS and reverse DNS for your hosts.
    That's unrelated to the static/sticky question.

    I'm sure it increases pressure on the IPv4 space. But perhaps it
    doesn't increase it all that much. At least for home users, many
    will want to be connected for much of the evening. You need enough
    IP addresses to handle the maximum load.

    If everybody turned off their equipment when they were not using it,
    you would have lots of free IP addresses at 3 a.m., but you wouldn't
    free up very many at 8 p.m. It's the peak load that counts for the
    number of IPs needed.
    Not really. The ISP still benefits from dynamic address assignment.
    That way it can move a block of IPs from one region to another,
    depending on where the load is. If everyone had static or sticky
    addresses, you would have to give your users advanced notification of
    IP address change before you could move blocks. And you would have
    to deal with irate customers who don't want to change.
    Neil W Rickert, Apr 14, 2005
  17. The big difference is that you configure static IPs manually, while
    sticky IPs are assigned automatically using a network protocol.

    What makes them sticky is that the server remembers what address it gave
    you last time you requested an IP, and makes an attempt to give you the
    same one this time.
    Barry Margolin, Apr 14, 2005
  18. I think he's seeing an artifact of the way DHCP works. When a DHCP
    client requests an IP, it includes the IP it would like to have, which
    is typically the last IP it had. If the IP is available, the server
    will assign that IP to the client.

    If the client doesn't specify a particular IP in its request, the server
    may remember the IP that it gave out to that MAC address last time, and
    give it out again if it's available.

    So what's probably happening when he switches from his router to his
    primary machine, is that the machine is proposing a different IP than
    the router had.
    Barry Margolin, Apr 14, 2005
  19. jrefactors

    Scooby Guest

    Speaking from not knowing any actual stats on this, I believe the pressure
    on the IPv4 space is not what it once was thought to be. The rfc's for
    private address space and NAT has freed up a lot of addresses. Now,
    companies with thousands of employees can accomplish their internal
    networking with private addressing. Even ISP's are using private addresses
    for their equipment that serves the internet. I'm sure the creation of
    broadband is now moving the trend back into the direction of using up more
    addresses, but I believe the situation is not critical at this point. There
    are still public blocks available if you can prove the need.

    Just MHO,

    Scooby, Apr 15, 2005
  20. jrefactors

    David Ross Guest

    If you have a static IP or block it is assigned to YOU by whoever is
    your upstream. It is a contracted thing or should be. And it should not
    change without consent or business interruptions such as the upstream
    going out of business.

    Dynamic means the IP can change at any time.

    I and others I know use sticky to refer to dynamic IPs that seem to stay
    the same for months on end. Here in central NC, TWC gives you an IP and
    you usually keep it for months. Then it might change to another in your
    subnet or I've even seen them reassign the area to a different /8.

    At the other end Bellsouth changes IP addresses everytime you
    authenticate via PPPoE. Or they used to, I don't use them much anymore.
    David Ross, Apr 15, 2005
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