Bug 97686

Summary: DNS failing to punch through firewall due to indescriminate grep in ifup-post
Product: [Retired] Red Hat Linux Reporter: Martin Ebourne <fedora>
Component: initscriptsAssignee: Bill Nottingham <notting>
Status: CLOSED RAWHIDE QA Contact: Brock Organ <borgan>
Severity: medium Docs Contact:
Priority: medium    
Version: 9CC: rvokal
Target Milestone: ---   
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Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: 7.25-1 Doc Type: Bug Fix
Doc Text:
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Last Closed: 2003-06-19 18:03:01 UTC Type: ---
Regression: --- Mount Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Flags
Proposed patch as detailed in text none

Description Martin Ebourne 2003-06-19 11:02:06 UTC 
From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.3.1) Gecko/20030510

Description of problem:
ifup-post contains code to open the firewall for DNS replies when PEERDNS=yes.

However, there is a grep to prevent the repeated addition of DNS rules, as in:

    if ! iptables -L RH-Lokkit-0-50-INPUT -n | grep -q $nameserver ; then

This of course matches any rule which the nameserver IP address is entered for.
Hence if your DNS server (or relay) has other services (smtp, etc) which the
firewall is explicitly open for, then the nameserver entries are not added and
DNS fails to work.

I have changed mine to:

    if ! iptables -L RH-Lokkit-0-50-INPUT -n | grep -q "$nameserver.* --sport 53
" ; then

This slightly more specific grep ensures that only DNS lines are considered.

Version-Release number of selected component (if applicable):
initscripts-7.14-1

How reproducible:
Always
Comment 1 Martin Ebourne 2003-06-19 11:03:43 UTC 
Created attachment 92481 [details]
Proposed patch as detailed in text
Comment 2 Bill Nottingham 2003-06-19 18:03:01 UTC 
Thanks, added to CVS. Will be in 7.25-1.