Martin Paul Eve bio photo

Martin Paul Eve

Professor of Literature, Technology and Publishing at Birkbeck, University of London

Email Books Twitter Github Stackoverflow MLA CORE Institutional Repo Hypothes.is ORCID ID  ORCID iD Wikipedia Pictures for Re-Use

Using British Library wifi when DHCP fails

Sometimes, the free wireless service at the British Library goes pear shaped and, if you are accustomed to using it, this can make research quite hard. Occasionally, however the fault is not with the central mechanism but rather with DHCP -- the mechanism that gives your computer an address on their system.

I'm afraid that this is a somewhat technical post, as I don't have time to write a user-friendly (aka. Windows) guide, but to determine if DHCP is at fault (assuming you are using a *nix based system, such as Linux or Mac OS X) you can issue, at a terminal:

cat /var/log/syslog | grep DHCP

once you've tried, probably unsuccessfully, to connect.

If you see lines like this:

Oct 27 10:11:10 allusion dhclient: DHCPDISCOVER on wlan0 to 255.255.255.255 port 67 interval 6
Oct 27 10:11:10 allusion dhclient: DHCPOFFER of 192.168.5.218 from 192.168.4.1
Oct 27 10:11:10 allusion dhclient: DHCPREQUEST of 192.168.5.218 on wlan0 to 255.255.255.255 port 67
Oct 27 10:11:13 allusion dhclient: DHCPREQUEST of 192.168.5.218 on wlan0 to 255.255.255.255 port 67
Oct 27 10:11:21 allusion dhclient: DHCPDISCOVER on wlan0 to 255.255.255.255 port 67 interval 3
Oct 27 10:11:21 allusion dhclient: DHCPOFFER of 192.168.5.218 from 192.168.4.1
Oct 27 10:11:21 allusion dhclient: DHCPREQUEST of 192.168.5.218 on wlan0 to 255.255.255.255 port 67

Then it might be fixable.

Indeed, simply set your wireless adapter to use a static IP, using the address shown in the DHCPOFFER line, a default gateway of 192.168.4.1 and DNS server likewise 192.168.4.1

Tada -- back online.