sed to replace a line with regular expression -

i want use sed replace ip addresses in below entry.

1500.arp1.akaarp.net.00000000.7ac112c6.123456.6 30 in txt "198.18.193.23,2509.417\;198.18.193.25,2609.417\;198.18.193.27,2709.417" 

1500.arp1.akaarp.net.00000000.7ac112c6.123456.6 30 in txt "19.18.19.27,1110.400\;198.18.193.25,2609.417\;198.18.193.27,2709.417"

i tried following :

sed -i s/"198.18.193.23,2409.417\;198.18.193.25,2609.417\;198.18.193.27,2709.417"/"198.18.19.27,1110.400"/ filename.txt

the above entry works if there 1 ip address in actual entry. if there multiple ip addresses separated regular expressions doesn't work.

your question extremely unclear if want replace whatever list of ip addresses between quotes that's just:

$ sed 's/"[^"]*"/"198.18.19.27,1110.400"/' file 1500.arp1.akaarp.net.00000000.7ac112c6.123456.6 30 in txt "198.18.19.27,1110.400" 

if that's not want edit question clarify requirements. in particular explain these 2 sentences in question mean:

1. the above entry works if there 1 ip address in actual entry.
2. if there multiple ip addresses separated regular expressions doesn't work.

the above run on input file:

$ cat file 1500.arp1.akaarp.net.00000000.7ac112c6.123456.6 30 in txt "198.18.193.23,2509.417\;198.18.193.25,2609.417\;198.18.193.27,2709.417"