Kitz Forum
Broadband Related => Broadband Hardware => Topic started by: broadstairs on November 27, 2017, 03:00:10 PM
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For an unrelated reason to this inquiry I was looking at my routers log and notice that about every 7 minutes 30 seconds I am seeing the following entries repeated
udhcpc: Sending renew...
udhcpc: Lease of 80.43.xxx.xxx obtained, lease time 900
udhcpc: dhcpMsgSend: msgType[-2147483596]
I am puzzled as to why this needs to happen so often, I know that this is micro-DHCP-Client and as such part of DHCP or rather the micro one which is part of busybox?
Stuart
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Is the IP changing each time? Is that your IP?
The lease time is set to 900 (15 mins) and as it should the DHCP tries to renew at 50%. If that's your WAN IP then no idea why Talktalk would set the lease time so low.
No idea what else would trigger such warnings.
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Yes it is my line's IP address (forgot to obliterate part which I've done now). I'll ask TT why this is.
Stuart
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Just searched the TT forums and in one thread it was said that if you have a Broadcom chipset the lease should be permanent but with Lantiq and others it may be 15 minutes. someone else suggested it could be that no Option 60 is set and that is why. I have a VMG3925 router which is a Broadcom unit so that should according to the comments I read give me a permanent lease. I dont get any obvious drops of the line or IP changes. It was suggested that the TT Super Router passes Option 60 to TT which then gives a permanent lease. If this is true it's a way of TT making it difficult for non TT supplied routers to be used. TT uses IPOE btw not PPPOE.
I'd be interested in others views but I think I will ask on their forum anyway as the threads I found are over 12 months old.
Stuart
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I have been asked by the TT team if I can set the WAN lease time on the router, well no there is no WAN option to set the lease time on my router. However I was wondering if anyone here knows if this can be set by command from Telnet?
Stuart
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I've changed the thread title to something more relevant.
I am waiting on TT to answer some questions. However I have a couple for folks here.
Is Option 43 required for UK VDSL and if so any idea what it is used for? Second I gather TT use Option 60 to pass a string back which has been reported as identifying their super router however if I try to add the same string on my VMG3925 it gets rejected by the GUI, so what is the format required for Option 60. Does this mean that they may have messed with the f/w on their HG635 to allow their specific format.
Stuart
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If rejected via GUI export config, edit in Notepad and then restore config. It is what I do to add "DNS" entries with a period in them on my VMG8324 so something similar may work on your model for your problem. To help you find the setting in the text file try to set it to something in the GUI you can search the text file for. Obviously do at your own risk.
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If rejected via GUI export config, edit in Notepad and then restore config. It is what I do to add "DNS" entries with a period in them on my VMG8324 so something similar may work on your model for your problem. To help you find the setting in the text file try to set it to something in the GUI you can search the text file for. Obviously do at your own risk.
Thanks I might try that later.
I have had an update from the TT folks but as often happens all they want me to do is try a different router :o shows how much they know about DHCP ;) I have updated them with an explanation of how it works and asked them to pass it on to their network team for an explanation of why their DHCP server sets a 900 second lease time. Now to wait for a reply.
Stuart
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Does anyone know definitively whether a lease renew should drop and reconnect or simply extend the lease?
Stuart
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The router should request for the lease time to be extended when it gets to 50%.
Talktalk appear to have had this configuration for some time now.
https://community.talktalk.co.uk/t5/Fibre-Broadband/DHCP-lease-from-TalkTalk-only-15-minutes/td-p/1766450
https://community.talktalk.co.uk/t5/General-Technology-Tips-Tricks/DHCP-Lease-Only-15-Minutes/td-p/2068175
Why they would set it so low is beyond me.
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Yes I've seen these and some others. It has been suggested on there that a renew will NOT drop the connection for a short time but others say it does. I am still hoping to get this passed to their network team for a proper explanation of why this happens but as yet it has not.
Stuart
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I am still getting nowhere with TT trying to get an answer as to why they set this lease time. The staff seem reluctant to get any proper answer which leads me to believe they are hiding something. I have had one more go today since returning from a brief holiday and will see if I can finally get an answer. If not then I guess I'll be raising another issue via the CEO office. I just dont know why they cannot answer this simple question - very frustrating.
Stuart
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If rejected via GUI export config, edit in Notepad and then restore config. It is what I do to add "DNS" entries with a period in them on my VMG8324 so something similar may work on your model for your problem. To help you find the setting in the text file try to set it to something in the GUI you can search the text file for. Obviously do at your own risk.
I have jsut reid this on my spare VMG3925 but it does not save it in the config, or at least not in anyway which I can identify.
Stuart
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Sorry I would try to assist more but I do not know the option myself. I would have thought it must be in the text file (unless it does not save it due to security reasons or it saves it encrypted). Perhaps someone else knows what to look for?
Also perhaps try Zyxel support they may reduce the validation checking in a future firmware or know of a method to workaround?
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Strange thing is that the data is saved across a power cycle. I can find what looks like Option 60 related stuff in the config file but my data is not in there.
Stuart
I've tried variations on the string and it seems that the GUI does not like the < and > characters in the Vendor ID string associated with Option 60, both norma; brackets and curly braces work OK however I dont yet know if the TT server will accept this.
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Could try saving configuration and then changing the option (nb it must be accepted by GUI) and saving again. Then use WinMerge to compare the two files to find the differences. Obviously be careful you are not resyncing too many times to upset the DLM!
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Just to confirm I'm doing the testing on a spare VMG3925 which is NOT connected to the net.
One more update today on my TT thread and one of their staff denies they use 15 minute lease times! Both myself and one other there have posted images to show that the staff member is WRONG!
Stuart
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Well believe it or not I finally have an answer on this from TT. They use a 15 minute lease in order to prevent running out of IPv4 addresses :o They seem to think that this will make sure they get back IPv4 addresses from VDSL customers more frequently. I have pointed out that perhaps if they actually moved to the 21st Century and started to support IPv6 then things might improve. OK perhaps a 24 hour lease might be too long as I know some folks do turn their routers off at night but maybe something like 8 hours might be more reasonable. Anyway I have suggested that the should move to the 21st Century and invest in IPv6 technology. I am fed up with having to run Miredo on Linux to access any site which is IPv6 only. They really are dinosaurs. :rant:
Stuart
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yes its more then likely to preserve ips, dual stack will have no immediate benefit on this but of course dual stack is the first step to a ipv6 internet so any sane isp should not be ipv4 single stacked
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For an unrelated reason to this inquiry I was looking at my routers log and notice that about every 7 minutes 30 seconds I am seeing the following entries repeated
Does this affect you in any way?