# problems with network connection - reject NAK [SOLVED]

## Despot Despondency

Hi,

Sorry if this has been posted before but I can't find a solution anywhere. I am having problems with the wired network connection on my computer. At the moment when I boot the computer I often get the message

```

dhcpcd[13584]: eth0: reject NAK via 192.168.1.254

```

repeated until dhcp times out and I have no network connection. 

I know I should be able to create a connection manually but I want it done automatically at boot up with dhcp.

Any pointers would be greatly appreciated.

TAILast edited by Despot Despondency on Sat Jun 25, 2011 6:21 pm; edited 1 time in total

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## DONAHUE

If 192.168.1.254 is in fact your dhcp server,  see if editing /etc/dhcpcd.conf to comment out  *Quote:*   

> require dhcp_server_identifier

  to  *Quote:*   

> # A ServerID is required by RFC2131.
> 
> #require dhcp_server_identifier

  cures the problem.

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## Despot Despondency

Hi, thanks for the response.

I tried your suggestion. I now get the messages 

```

dhcpcd[13577]: eth0: broadcasting for a lease

dhcpcd[13577]: eth0: offered 192.168.1.64 from 192.168.1.254

dhcpcd[13577]: eth0: NAK: requested address is not available via 192.168.1.254

```

repeated until it times out again.

Any other suggestions?

----------

## DONAHUE

try a fixed ip

or try dhclient vice dhcpcd

check router configuration for access lists

firewall? 

proxy server?

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## Despot Despondency

Hello again.

I don't have a firewall or proxy server set up. This is a fresh install so I only have the bare basics set up.

I managed to set up a static ip. I used the ip address etc that dhcp used last time it successfully loaded the network.

I am confused about why dhcp keeps failing sporadically? 

Also, what do you mean by 

 *Quote:*   

> 
> 
> check router configuration for access lists 
> 
> 

 

?

Thanks again.

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## DONAHUE

The problem most likely relates to either the router or dhcpcd or both not being totally compliant with the same set of rules.

Most routers can be setup to allow connection from only a limited set of ip's or mac addresses (sic access list).

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## Despot Despondency

OK, that makes sense. 

It's weird though. I've had this router for over a year and it's always been fine before.

Is there anyway to resolve this? 

Otherwise I just start using a static ip permanently. Is there anything I need to take into account when doing this, e.g. security issues with certain ranges of addresses? Sorry if this is a stupid question.

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## DONAHUE

reasonable question, I would try to determine the range of IP's the router uses for dhcp leases and use a fixed IP outside the range. A fixed IP could actually be more secure. Router updates, dhcpcd revisions, neighbor on the same frequency..

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## Despot Despondency

Sorry for late response. I've had paper deadlines and a holiday and this is the first chance to sort out my computer.

Thanks for the help. Everything seems to be working fine now.

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## bwhmather

Couple of weeks slow but I have encountered this problem.

In my case setting the clientid option in dhcpd.conf did the trick.

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