Sky IP started changing

Hey everyone,

I currently have sky adsl2 which has been installed for about 4 months (recently moved to a new house).

For the first 3 months, the ip address I had was the same. However, just recently it has started changing every day. I know that I don't have a static IP so it could change often but has anyone else noticed that their ip address has started changing frequently?

My connection drops about 3 times a day and has every since I moved in and I have no interest in trying to get it fixed. My openreach experience has always been negative - not had a single issue fixed... ever. I'm guessing that because my connection is dropping, I'm getting a new ip on each reconnection. However for the first 3 months disconnections never use to change my ip.

My router is turned on at all times.

Anyone else having similar experiences?

Likely you have changed from MER (sticky IP) to PPPoA (fully dynamic).

No way around the changing IP address issue other than fixing the fault and getting a decent uptime going.

Hi Oliver.

Thanks.... I didn't realise that there were two different dynamic ip systems in place. I have always had the same IP upon reconnecting with every isp i have ever had, unless i left the router/modem disconnected for a period of time.

Sky have been transition ADSL customers from MER to PPPoA for a long while now. VDSL customers all use the "sticky" MER system.

Hmmm. Not sure I'd call the 1hr lease I get from Sky Fibre "sticky". Virgin's (120/12) 7 day lease is "sticky".

MER.... that's sending option 60, client id, with the dhcp request, right?

In reply to a post by clivem:

Hmmm. Not sure I'd call the 1hr lease I get from Sky Fibre "sticky". Virgin's (120/12) 7 day lease is "sticky".

It's not the length of the lease that's important, but whether the same IP address is issued each time a lease expires (which in Sky's case, it usually is).

In reply to a post by clivem:

MER.... that's sending option 60, client id, with the dhcp request, right?

DHCP option 61 I think.

In reply to a post by Oliver341:

It's not the length of the lease that's important, but whether the same IP address is issued each time a lease expires (which in Sky's case, it usually is).

Even on that basis I wouldn't call it sticky, every single time I've let the 1 hour lease lapse, (even by 5 seconds), without renewing before expiry time, I've been allocated a new IP address. Not once have I been re-allocated the same IP address.

In reply to a post by Oliver341:

DHCP option 61 I think.

According to some online documentation, option 61 is used for the authentication details. Option 60 is used for the Sky router version and other information, but this is documented as not necessarily required.

In reply to a post by David_W:

According to some online documentation, option 61 is used for the authentication details. Option 60 is used for the Sky router version and other information, but this is documented as not necessarily required.

Option 61 == client Id. (My bad.) That's needs to be populated to get an IP. Option 60, (Vendor Id), which the SR101 does populate, definitely isn't required to be populated to obtain an IP when using a 3rd party router.

In reply to a post by clivem:

Even on that basis I wouldn't call it sticky, every single time I've let the 1 hour lease lapse, (even by 5 seconds), without renewing before expiry time, I've been allocated a new IP address. Not once have I been re-allocated the same IP address.

It must have changed then. In the year that my Sky ADSL connection had MER I had the same IP address all the time, despite various lease expiries.

I still get the same IP 99% of the times on MER that said my connection doesn't drop out ever so I very rarely disconnect.

Edited by ukhardy07 (Fri 11-Oct-13 19:26:15)

In reply to a post by ukhardy07:

I still get the same IP 99% of the times on MER that said my connection doesn't drop out ever so I very rarely disconnect.

Well, that is going to help! If you don't disconnect and your router always renews DHCP lease every hour, you'll keep the same IP.

Sky DHCP IP allocation for MER Fibre, at least from what I have seen......

First time DHCP request from client, you'll get an IP with a lease of 10 mins. If you renew before the lease expires, you'll get the same IP with a lease time of 1 hour. As long as you keep renewing before the 1 hour expires, you'll keep the same IP with a lease time of 1 hour.

I've not seen any stickyness. Lease expires, even by 1 second, IP is returned to DHCP pool and you'll get another.

Edited by deleted (Fri 11-Oct-13 20:30:28)

There's definitely at least been some stickiness.

I've had building works carried out with electric down for a few days and got the same IP back.
& powercuts lasting a few hours often give me the same IP

I haven't disconnected in a long time so cannot comment on whether that's changed recently but certainly 6 months ago it wasn't giving me new ones willy nilly. Perhaps just flook though.

In reply to a post by clivem:

Well, that is going to help! If you don't disconnect and your router always renews DHCP lease every hour, you'll keep the same IP.

The way the DHCP client works is that it will start requesting a lease renewal after half the lease time, in Sky's case after 30 mins, so in reality if there aren't any problems the lease is renewed every 30 minutes.

if he is on pppoa then extending the ppp timeout on the router so its longer than a resync takes may allow the ip to stay (this works on BT). But with the caveat been accept the ip profile will not update, of course sky dont use ip profiles, so he basically should have no noticeable downside doing this.