Thread: Problem getting VPN to work with resolvconf & dnsmasq

my main laptop running ubuntu 12.10 64bit desktop. access corporate intranet need run proprietary vpn solution (lotus mobility client, or lmc) works - has great features. however, expect, lmc not integrated network manager @ all, , writes directly /etc/resolv.conf, inserting vpn domain @ head of search list, , vpn nameservers before existing ones. usual, causes problems local name resolution when working home network.

last couple of days i've been trying make vpn play nice resolvconf , new local resolver (dnsmasq), trying resolver handle vpn smoothly. since vpn proprietary, options configuration limited. best can (as far can tell) prevent updating /etc/resolv.conf @ all, , can have start program of choice when vpn established. since know nameservers , domain within corporate intranet vpn configure, surely can configure them manually?

after reading resolvconf documentation find, , design brief dns resolver changes in 12.04, , various outstanding bugs, decided best option set vpn not update /etc/resolv.conf, , have script invoked vpn client use resolvconf update resolver manually.

vpn creates interface called "wc0", see:

code:

$ ifconfig -a -s  iface   mtu met   rx-ok rx-err rx-drp rx-ovr    tx-ok tx-err tx-drp tx-ovr flg  eth0       1500 0   2584463      0      0 0       4905490      0      0      0 bmru  lo        16436 0     81161      0      0 0         81161      0      0      0 lru  wc0        1348 0        11      0      0 0            44      0      0      0 mopru  wlan0      1500 0     31160      0      0 0           835      0      0      0 bmru

i generated file called resolv.wc0 containing analogous to:

code:

search abc.com  nameserver 1.2.3.4  nameserver 1.2.3.5

i established vpn, , ran command "sudo resolvconf -a wc0.lmc < resolv.wc0".

abc.com added search terms in /run/resolvconf/resolv.conf, linked /etc/resolv.conf, should be. there no change nameserver entry, still contains 127.0.1.1, serviced dnsmasq. however, attempting ping known server (server.abc.com) inside vpn intranet results in failure resolve name. issuing dig @1.2.3.4 server.abc.com resolves perfectly, have working connection on vpn, , nameservers up. appears resolver (dnsmasq) not being updated resolvconf.

running "sudo resolvconf -d wc0.lmc" undoes manual changes, removing abc.com search terms in /run/resolvconf/resolv.conf again. leaves me out of ideas, , open suggestions on need differently make name resolution within vpn work. help!

the local forwarding nameserver listening @ 127.0.1.1 instance of dnsmasq controlled directly networkmanager , fed nameserver information exclusively networkmanager. on machine networkmanager not aware of nameservers on vpn , nm-dnsmasq doesn't know these nameservers. telling resolvconf vpn nameservers doesn't because networkmanager not obtain information resolvconf. (the standalone dnsmasq instance "dnsmasq" package *is* supplied nameserver information resolvconf, that's not relevant here.)

using networkmanager establish lan connection , lmc vpn client establish vpn connection? if should suffice (1) disable networkmanager-controlled instance of dnsmasq. edit (with root privileges) /etc/networkmanager/networkmanager.conf , comment out line "dns=dnsmasq" looks "#dns=dnsmasq"; "sudo restart network-manager". once done, nm won't run slave dnsmasq instance feeds nameserver information; instead feed nameserver information resolvconf , resolvconf able combine information information provided command "sudo resolvconf -a wc0.lmc < resolv.wc0".

have change 1 other thing. resolvconf prioritizes nameserver addresses according interface type. list, in order of priority, of interface types can found in /etc/resolvconf/interface-order. networkmanager's information registered under name 'networkmanager' matches on last line of list. record name, 'wc0' match on last line , sort after 'networkmanager'. change this, (2) add line 'wc*([^.]).lmc' after 'tap*' line in /etc/resolvconf/interface-order.

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