I can reach Server2 = ns2.cartouche.org.uk ip = ending.242 via ping and HTTP (to IP address) but not Server 1 = ending.241 (no response). This is the opposite of your description (you say you can reach Server 1 but not Server 2).
Through other tests, I figured out the following:
1. Your ns.cartouche.org.uk server does not respond at all.
2. Your ns2.cartouche.org.uk server does not respond to DNS requests with a server name. Hence, the client cannot verify it is talking to the correct server and the request fails (at least partially).
Below are results of some of my queries that may help you isolate the problems. Securing and maintaining DNS servers isn't easy. My choice was to farm it out to www.DNSmadeEasy.com (who provides secure, redundant servers that reside on major backbones and update other servers extremely quickly for very little money). Two reasons why I outsource DNS services is 100% availability guarantee with (not just five 9s) and off-site management in case of catastrophes or DDoS attacks (you can redirect the IP addresses to servers on another site -- even if they just say "server maintenance - please come back later").
nslookup to the DNS server of my local ISP gives the following results:
>nslookup cartouche.org.uk
Non-authoritative answer:
Name: cartouche.org.uk
Address: 81.131.71.241
>nslookup ns2.cartouche.org.uk
Non-authoritative answer:
Name: ns2.cartouche.org.uk
Address: 81.131.71.242
>nslookup ns.cartouche.org.uk
*** [My ISP's DNS server] can't find ns.cartouche.org.uk: Non-existent domain
Because cartouche.org.uk resolves but ns.cartouche.org.uk doesn't, I would guess ns.cartouche.org.uk is undefined in your DNS table (i.e. no entry for host "ns").
These results are also peculiar:
>nslookup www.cartouche.org.uk
Non-authoritative answer:
Name: cartouche.org.uk
Address: 81.131.71.241
Aliases: www.cartouche.org.uk
HTTP to www.cartouche.org.uk works but HTTP to IP address does not. This could be a peculiarity of the Abyss web server you're using or possibly some port forwarding happening somewhere.
However, FTP requests ftp.cartouche.org.uk and 241 both give a login prompt.
>nslookup cartouchehosting.com ns2.cartouche.org.
uk
*** Can't find server address for 'ns2.cartouche.org.uk':
Non-authoritative answer:
Name: cartouchehosting.com
Address: 81.131.71.242
>nslookup cartouchehosting.com 81.131.71.242
*** Can't find server name for address 81.131.71.242: Non-existent domain
Server: UnKnown
Address: 81.131.71.242
Name: cartouchehosting.com
Address: 81.131.71.242
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A free DNS test on http://www.infoblox.com/services/dns_advisor.cfm (I gave a fake e-mail address) gives the following results fr DNS configuration:
Test Summary
TOTAL TESTS COMPLETED = 69
Severe problem = 20
Serious problem = 6
Potential problem = 14
Configured correctly = 29
Details (this list is truncated, it's better if you perform the test yourself):
Lookup SOA for zone cartouche.org.uk has an SOA record, proceeding...
Lookup NS RRs at parent Found: ns2.cartouche.org.uk., ns.cartouche.org.uk.
Check >1 NS RR 2 NS records found: ns2.cartouche.org.uk., ns.cartouche.org.uk.
Check NS RRs are valid names ns.cartouche.org.uk. is a valid name
Check NS RRs are valid names ns2.cartouche.org.uk. is a valid name
Lookup NS RRs at auth. name servers ns.cartouche.org.uk. returned: no nameservers
Lookup NS RRs at auth. name servers ns2.cartouche.org.uk. returned: no nameservers
Check >1 NS RR ns.cartouche.org.uk. returned: query timed out
Check >1 NS RR ns2.cartouche.org.uk. returned: query timed out
Check NS RRs are valid names ns.cartouche.org.uk. is a valid name
Check NS RRs are valid names ns2.cartouche.org.uk. is a valid name
Compare auth and parent NS RR sets ns.cartouche.org.uk. returned: query timed out
Compare auth and parent NS RR sets ns2.cartouche.org.uk. returned: query timed out
Lookup A RRs for NS names Query for ns.cartouche.org.uk. returned: NXDOMAIN
Lookup A RRs for NS names Query for ns2.cartouche.org.uk. returned: NXDOMAIN
Check for matching glue records ns.cartouche.org.uk. returned: query timed out
Check for matching glue records ns2.cartouche.org.uk. returned: query timed out
Check NS addresses on >1 network 0 nameserver A records found
Check for CNAMEs Query for ns.cartouche.org.uk. returned: NXDOMAIN
Check for CNAMEs Query for ns2.cartouche.org.uk. returned: NXDOMAIN
Check NS address PTR matches NS name ns.cartouche.org.uk. NS addresses do not have matching PTRs
Check NS address PTR matches NS name ns2.cartouche.org.uk. NS addresses do not have matching PTRs
Fingerprint nameserver ns.cartouche.org.uk. is
Fingerprint nameserver ns2.cartouche.org.uk. is
Check fingerprint for vulnerable version
Check fingerprint for vulnerable version
Send VERSION.BIND query ns.cartouche.org.uk. returned: query timed out
Send VERSION.BIND query ns2.cartouche.org.uk. returned: query timed out
Send SOA query ns.cartouche.org.uk. returned: query timed out
Send SOA query ns2.cartouche.org.uk. returned: query timed out
Measure response time ns.cartouche.org.uk. SOA query was not successful
Measure response time ns2.cartouche.org.uk. SOA query was not successful
Check for AA bit ns.cartouche.org.uk. returned: query timed out
Check for AA bit ns2.cartouche.org.uk. returned: query timed out
Compare all SOA MNAME fields No SOA records found
Compare all SOA RNAME fields No SOA records found
Compare all SOA SERIAL fields No SOA records found
Compare all SOA REFRESH fields No SOA records found
Compare all SOA RETRY fields No SOA records found
Compare all SOA EXPIRE numbers No SOA records found
Compare all SOA NEGTTL numbers No SOA records found
Examine SOA refresh SOA refresh is 86400
Examine SOA retry SOA retry/refresh ratio is 0.04
Examine SOA e